Chevrolet - RV - Parts Catalogue - 1990 - 1990

1991 ELECTRICAL DIAGRAMS AND DIAGNOSIS MANUAL F t/V , P M O D E L S When reference is made in this manual to a brand name, number, or specific tool, an equivalent product may be used in place of the recommended item. All information, illustrations, and specifications contained in this manual are based on the latest product information available at the time of publication approval. The right is reserved to make changes at any time without notice. No part of this publication may be reproduced, stored in any retrieval system or transmitted, in any fornror by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the GMC Truck Division of General Motors Corporation. This includes all text, illustrations, tables and charts. X-9140 © 1990 General Motors Corporation June 1990 All rights reserved. Printed in U.S.A. NOTICE CONTENTS SENSITIVE TO STATIC ELECTRICITY F-05403 ELECTRONIC DISCHARGE WARNING When handling an electronic part that has an ESD sensitive sticker, the service technician should follow these guidelines to reduce any possible electrostatic charge build-up on the service technician’s body and the electronic part in the dealership. 1. 2. 3. 4. Do not open the package until it is time to install the part. Avoid touching the electrical terminals of the part. Before removing the part from its package, ground the package to a known good ground on the vehicle. Always touch a known good ground before handling the part. This should be repeated while handling the part and more frequently after sliding across the seat, sitting down from a standing position or walking a distance. 1991 R/V, P TRUCK MODELS TABLE OF CONTENTS INTRODUCTION Circuit Operation Page Page Introduction ...................................................................................... How to Use This Manual ................................................................. Handling Electrostatic Discharge (ESD) Sensitive P a r ts ................................................................... Circuit O p eratio n............................................................................... Circuit Diagrams ............................................................................... Component Locations ...................................................................... Diagnosis ...................................................................................... Basic Electricity ............................................................................. Circuit Malfunctions.......................................................................... Electrical Test Equipment............................................................. Circuit Wiring Repair Procedures ................................................ Weather-Pack Connectors ........................................................... Metri-Pack Connectors .................................................................. Special T o o ls ...................................................................................... Regular Production Option (RPO) List .......................................... Abbreviation List ............................................................................... General Index .................................................................................... ......... ......... 3 3 ......... ......... ......... ......... 3 3 3 3 4 4 4 4 ......... ......... ......... ......... ......... ......... ......... 6 8 8 ......... 9 ......... 10 ......... 10 Index 1 R/V TRUCK MODELS - SECTION A Page Phantom Views ............................................................................... Symptom Index ............................................................................... Power Distribution .......................................................................... Fuse Block D e ta ils .......................................................................... Bulb Data and Fuse Block Identification ....................................... Ground Distribution ........................................................................ ......... A-2 ......... A-8 . . . . A-10 . . . . A-14 . . . . A-15 A-16 Circuit Operation Page Headlamps (B a s e )............................................................................... Canadian Daytime Running Lamps................................................... Quad H a lo g en ...................................................................................... Hazard L a m p s ...................................................................................... Front Park and Sider Marker Lam ps................................................. Turn L am p s........................................................................................... Horns .................................................................................................... Cigarette Lighter ............................................................................. Windshield Wipers and Washers (Pulse).......................................... Start and C h a rg e ................................................................................. Auxiliary Cooling F a n .......................................................................... .... .... .... .... .... .... .... .... .... .... .... A-23 A-23 A-23 A-33 A-33 A-42 A-48 A-48 A-50 A-53 A-89 Circuit Diagram Page A-25 A-26 A-32 A-34 A-36 A-44 A-49 A-49 A-52 A-55 A-90 Air Conditioning.............................................................................................. A-91 H e a te r............................................................................................................... A-91 Auxiliary Heater ............................................................................................... A-91 Gages and Warning Indicators.....................................................................A-100 Audio Alarm M odule....................................................................................... A-111 Rear Wheel Antilock Brakes/Brake Warning ............................................. A-114 Dome L a m p s ................................................................................................... A-118 Cruise Control .................................................................................................A-122 Four-Wheel D riv e ............................................................................................ A-125 Power Mirrors and Door L o c k s ........................................................... .. A-127 Power W indow s...............................................................................................A-136 Radio AM and AM/FM S te re o .......................................................................A-143 Rear D efo g g er................................................................................................. A-146 Rear L a m p s ......................................................................................................A-149 Rear Park and Marker L a m p s .......................................................................A-149 Taillam ps.......................................................................................................... A-149 Trailer T o w ........................................................................................................ A-149 Backup Lam ps................................................................................................. A-149 License Lam ps................................................................................................. A-149 Vacuum S ystem s............................................................................................ A-161 Component Locator V ie w s ............................................................................A-166 Component Locater Index ............................................................................A-194 ECM Pinouts ............................... PCM Pinouts ............................... TCM Pinouts ............................... PCM Inputs ................................. PCM O utputs............................... TCM ............................................. Hot Fuel Handling ..................... Torque Converter Clutch Control Ignition ........................................ ECM Inputs ................................. ECM O utputs............................... Fuel Control and Idle Air Control Instrument C lu s te r..................... Circuit Diagram Page A-94 A-96 A-99 A-104 A-112 A-116 A-119 A-124 A-126 A-129 A-139 A-144 A-147 A-156 A-150 A-160 A-154 A-158 A-164 A-57 A -66 A-67 A-68 A-70 A-72 A-79 A-74 A-76 A-63 A-64 A-78 A-103 TABLE OF CONTENTS 1 P TRUCK MODELS - SECTION B P MOTORHOME - SECTION C Page Page Phantom Views ................................................................................................. B-2 Symptom Index ................................................................................................. B-3 Power Distribution .............................................................................................B-4 Fuse Block D e ta ils .......................................................................................... B-10 Lamp Bulb D a ta ............................................................................................... B-14 Ground Distribution ........................................................................................ B-15 C irc u it O p e ra tio n Page Headlamps (B a s e ).......................................................................................... .B-22 Canadian Daytime Running Lam ps...............................................................B-25 Park, Marker and Hazard Signal L a m p s .................................................... .B-30 Turn L a m p s ...................................................................................................... .B-33 Horns .................................................................................................................B-35 Windshield Wipers and Washers ................................................................ .B-37 Starting/Charging..............................................................................................B-39 Glow Plugs ...................................................................................................... .B-59 Fuel C ontrols.....................................................................................................B-62 Instrument Panel ..............................................................................................B-66 Indicator L a m p s ............................................................................................... .B-66 G a g e s .................................................................................................................B-66 Instrument Panel Lam ps..................................................................................B-66 Brake Warning S ystem ................................................................................... .B-73 Rear Exterior Lam ps.........................................................................................B-75 Backup Lam ps................................................................................................. .B-75 Taillamps, Rear Marker and License Lamps ............................................. .B-75 Vacuum S ystem ............................................................................................... .B-79 Component Locator V ie w s ............................................................................ .B-81 Component Locater Index ............................................................................ .B-87 ECM P in o u ts .......... ECM In p u ts ............ ECM O utputs.......... PCM P in o u ts .......... PCM In p u ts ............ PCM O utputs.......... TCM Pinouts .......... TCM Inputs/Outputs Instrument Cluster . 2 TABLE OF CONTENTS Phantom Views ................................................................................................ C-2 Symptom Index ................................................................................................ C-3 Power Distribution ........................................................................................... C-4 Fuse Block D e ta ils ........................................................................................... C-8 Lamp Bulb D a ta .............................................................................................. C-10 Ground Distribution ....................................................................................... C-11 Circuit Diagram Page B-23 B-27 B-31 B-34 B-36 B-38 B-40 B-60 B-63 B-70 B-71 B-72 B-74 B-76 B-77 B-78 B-80 B-43 B-44 B-46 B-49 B-50 B-52 B-55 B-56 B-69 Circuit Operation Page Headlamps (B a s e )......................................................................................... .C-13 Canadian Daytime Running Lam ps............................................................ .C-16 Park, Marker and Hazard Signal Lamps ................................................... .C-21 Turn L a m p s ......................................................................................................C-23 Horns .............................................................................................................. .C-25 Windshield Wipers and Washers ................................................................C-27 Starting/Charging........................................................................................... .C-29 Glow Plugs ......................................................................................................C-43 Fuel C ontrols.................................................................................................. .C-46 Auxiliary Cooling F a n .................................................................................... .C-48 Provisions for Air Conditioning.....................................................................C-48 Cruise C o n tro l................................................................................................ .C-51 Instrument Panel ........................................................................................... .C-53 Instrument C lu s te r......................................................................................... .C-53 Indicator L a m p s ...............................................................................................C-53 G a g e s .............................................................................................................. .C-53 Instrument Panel Lam p s............................................................................... .C-53 Provisions for Dome Lamps ........................................................................ C-53 Rear L a m p s ......................................................................................................C-60 Taillam ps.......................................................................................................... C-60 Backup Lam ps................................................................................................ .C-60 Vacuum S ystem ...............................................................................................C-64 Component Locator Views Component Locater Index Ignition ............................... PCM Pinouts ..................... PCM Inputs ........................ PCM O utp u ts..................... Throttle Body Injection . . . TCM Pinouts ..................... TCM Inputs/Outputs......... DRAC ................................. Circuit Diagram Page C-14 C-18 C-22 C-24 C-26 C-28 C-30 C-44 C-47 C-49 C-49 C-52 C-55 C-56 C-57 C-58 C-59 C-62 C-63 C-65 C-66 C-70 C-32 C-33 C-34 C-36 C-38 C-39 C-40 C-42 Circuit diagrams provide a schematic picture of how a circuit is provided voltage, what the current path is to the components, and how the circuit is grounded. HOW TO USE THIS MANUAL NOTICE • • • • The purpose of this manual is to provide: Clean and simple electrical circuit diagrams. Discussion of circuit electrical operation. Simplified diagnosis and testing procedures. Component location views. • • • • Each electrical system or circuit will provide the follow­ ing information: Circuit Operation. Circuit Diagrams. Component Location. Diagnosis Charts. A 1. Do not open the package until it is time to install the part. 2. Avoid touching the electrical terminals of the part. 3. Before removing the part from its package, ground the package to a known good ground on the vehicle. 4. Always touch a known good ground before handling the part. This should be repeated while handling the part and more frequently after sliding across the seat, sitting down from a standing position or walking a dis­ tance. The following is a list of Zones for the vehicle: C O N T E N T S S E N S IT IV E TO S TA TIC E L E C T R IC IT Y HANDLING ELECTROSTATIC DISCHARGE (ESD) SENSITIVE PARTS When handling an electronic part that has an ESD sen­ sitive sticker (Figure 1), the service technician should fol­ low these guidelines to reduce any possible electrostatic charge build-up on the service technician’s body and the electronic part in the dealership: For ease of diagnosis, all connectors (C), splices (S), grounds (G) and grommets (GT) are identified by their own unique number. This number is used to reference component locations and also for identification in the diagnostic charts. The beginning digit designates the ZONE at which the connector, splice or ground can be found. For example: C302. The “C ” is for connector, the “3” represents Zone 300 and 02 is the connector number. ZONE LOCATION 100 — At and forward of bulkhead. 200 — Within l/R 300 — From l/P to rear of cab. 400 — Rearward of cab. 500 — Within left door. 600 — Within right door. 900 — Within rear doors. H A N D L E I N A C C O R D A N C E W IT H S T A T I C C O N T R O L P R O C E D U R E S G M 9107P A N D GM 9108P, O R G M D IV IS IO N A L S E R V IC E M A N U A L S . F -0 5 4 0 3 Figure 1 — Electronic Discharge Warning CIRCUIT OPERATION The description of circuit operation provides a simpli­ fied discussion of what is happening within each circuit. The discussion includes power application, ground paths and component operation. The explanation is tied to the circuit diagram, and in some cases, to specific switch movement or components in a circuit. All connectors are shown with their part numbers and are viewed from the mating end. The part number is used to save time when ordering replacement parts. All compo­ nents and switches are shown in their rest position, unless otherwise marked. COMPONENT LOCATIONS When you are ready to locate the schematic compo­ nents on the vehicle, use the Component Locations chart, see Figure 3. Listed in the LH column are the components shown on the schematic. Next to the Fuse Block is the location, “Behind LH side of l/R” Reference to LH and RH is made as though the technician were sitting in the driver’s seat. On the same line, in the far right column, is the page-figure reference. In this case, you are directed to Figure 37 in the Component Locator Views. Where connectors are listed, the number of cavities is provided. This represents the total number of cavities in the connector, regardless of how many are actually used. This information is provided to help you identify connec­ tors on the vehicle. Only in-line connector locations are given. Grounds are listed next in the table. The location description for ground G302 reads, “Behind LH side of IIP, on ALDL bracket.” You are directed to Figure 32. Nearly every component, connector, ground or splice shown on a schematic can be pinpointed visually by using the Component Location Views in the back of this manual. Each wiring circuit is identified by circuit number, size (in mm2) and color. Wire colors are shown in the abbrevi­ ated form. Figure 2 shows how the circuit numbers and color abbreviations are identified in this manual. There are three types of lines used to depict circuits throughout the circuit diagrams. They are as shown: CIRCUIT DIAGRAMS The circuit diagrams show the circuits and components that are covered in that particular system. By eliminating circuits and components not related to the systems being covered, the circuit diagrams are greatly simplified. ^ H 2 -s .o n E D B i^ Solid Color Circuit Line 2 - 3.0 r e d / w h t mm Circuit Line With Tracer RPO Variant Circuit Line COMPONENT LOCATION 9- -------------------- 1 COLOR OF WIRE INSULATION WIRE CIRCUIT -» NUMBER Page - Figure BRN L WIRE SIZE IN SQ. MM. B L K ___ .........Black BRN .........Brown GRN . . . .........Green ORN . . . GRA . . . ........... Gray RST . . . . ...........Rust P P L ___ YEL . . . . . . . . Yellow W H T ___ ___ White B L U .................... Blue P N K ....................Pink DK ......... ......... Dark L T ........... .........Light Headlamp Dimmer Switch........................................... Low Beam Headlamp Relay........................................ C100 (36 Cavities) (Diesel)......................................... .................... C100 (36 Cavities) (Gasoline)..................................... G104............................................................................ G105............................................................................ G302............................................................................ S101............................................................................. S102............................................................................. S103............................................................................. S104.............................................................................. S307.............................................................................. ..162-37 .. 162-36 ..171-57 Engine compartment, on LH front of dash.................. ..159-28 ..156-19 ... 149-5 .. 166-47 ..161-32 .166-47 .166-47 .166-47 steering column....................................................... Grommet 10Q................................................................ F-05975 Figure 2 — Wire Coding . 167-37 159-29 Figure 3 — Component Location Chart 3 Check for the cause of the problem (Diagnosis Charts) DIAGNOSIS Before beginning any diagnosis, there are several important steps that should be taken: Verify the problem The Diagnosis Charts (Figure 4) are a step-by-step approach to diagnosis of the problem (or condition). Each chart covers one symptom. For example, “Horn(s) will not operate.” Operate the system and list symptoms in order to: • Check the accuracy and completeness of the com­ plaint. • Learn more that might give a clue to the nature and location of the problem. • Analyze what parts of the system are working. Check the circuit diagram Refer to the Circuit Diagram for clues to the problem. Location and identification of circuit components may give some idea of where the problem is. The circuit diagrams are designed to make it easy to identify common points in circuits. This knowledge can help narrow the problem to a specific area. For example, if several circuits fail at the same time, check for a common voltage or ground connection. If part of a circuit fails, check the connections between the part that works and the part that does not work. For example, if the low beam headlamps work, but the high beams and the indicator lamp do not, then voltage and ground paths are good. Since the dimmer switch is the component which switches this voltage, it is most likely the cause of failure. Read “circuit operation” Read the Circuit Operation for the problem circuit. By studying the circuit diagram and circuit operation, enough information should be learned to narrow the cause to one component or one portion of the circuit. The charts are divided into three columns; Test, Result and Action. The Test procedures are listed in numerical sequence and must be followed in that order. Each test step will describe what must be done to the circuit, what test equipment to use and where to connect the test equip­ ment. After the test procedure has been performed, refer to the Result column. This will list possible results of the test. Once the result has been found, follow it directly over to the Action column. The Action column will instruct what must be done to correct the problem or will list the next test step to be per­ formed. It is important to remember that a problem in one sys­ tem could result in a symptom in another system. BASIC ELECTRICITY Ohm’s Law states that voltage (E) is equal to resistance (R) (ohms) time current (I) (amperes) in a circuit (E = R x I). The equation can also be shown as I = E/R or R = E/I. If any two of the values are known for a given circuit, the missing one can be found by substituting the values in amperes, volts or ohms and solving for the missing value. In a typical simple circuit, battery voltage is applied to a bulb through a 10-amp fuse and a switch. Closing the switch turns on the bulb. To find the circuit current flow, use the equation: Grounded Circuit (Figure 7) I = 12 volts (E)/2 ohms (R), or I = 6 amps. The bulb in this circuit operates at 6 amps and is rated to operate at this level. With 12 volts applied to the bulb, it will glow at the rated level. CIRCUIT MALFUNCTIONS There are three electrical conditions that can cause a non-working circuit; an “Open Circuit,” a “Short Circuit,” or a “Ground Circuit.” 1. Repair the problem circuit as directed in the diagnosis charts. Verify that the repair is complete Operate the system and check that the repair has removed all symptoms, and also has not caused any new symptoms. 2. 3. 4. RESULT Check condition of PARK LP fuse. Open Circuit (Figure 5) An open circuit occurs whenever there is a break in the circuit. The break can be corrosion at the connector, a wire broken off in a component, a wire that burned open from too much current, or a component not operating as it should. GO to step 2. Fuse is blown. LOCATE and REPAIR source of overload. Then, REPLACE fuse. With the light switch ON, connect a test lamp from ORN (240) wire at light switch connector C304 to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire from light switch to fuse block. Connect a test lamp from YEL (10) wire at light switch connector C 304 to ground. Test lamp lights. GO to step 4. Test lamp does not light. REPLACE light switch. Test lamp lights. REPAIR open in LT GRN (11) wire from dimmer switch to lights. Test lamp does not light. REPLACE dimmer switch. Figure 4 — Typical Diagnosis Chart 4 Figure 7 — Grounded Circuit JL JL ACTION Fuse is not blown. Connect a test lamp from LT GRN (11) wire at dimmer switch connector C305 to ground. A grounded circuit is like a short circuit but the current flows directly into a ground circuit that is not part of the original circuit. This may be caused by a wire rubbing against the frame or body. Sometimes a wire will break and fall against metal that is connected electrically to the ground side of the voltage supply. A grounded circuit may also be caused by deposits of oil, dirt or moisture around connections or terminals, which provide a good path to ground. Make the repair HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS— BOTH SIDES TEST Figure 6 — Short Circuit I = E/R. Filling in the numbers for the equation: 1 B-00723 Figure 5 — Open Circuit Short Circuit (Figure 6) A short circuit happens when the current bypasses part of the normal circuit. This bypassing is usually caused by wires touching, salt water in or on a component such as a switch or a connector, or solder melting and bridging con­ ductors in a component. ELECTRICAL TEST EQUIPMENT Various electrical testers have been developed over the years. A few of these are basic but are required to per­ form a thorough electrical diagnosis. These include: • Jumper wires • Voltmeter • Test lamps • Ohmmeter • Self-powered test lamps • Ammeter All of these testers come in a variety of models and any working model will be adequate for simple tests. However, accuracy becomes important when the value of a reading obtained using a meter is critical to the diagnosis proce­ dure. Make sure any electrical test meter used is of suffic­ ient quality and accuracy to make the measurements required in the electrical testing. Jumper Wires Jumper wires allow “jumping” across a suspected open or break in a circuit. • If the circuit works properly with the jumper wire in place, but does not work when the jumper wire is removed, the circuit has an open spot. • A circuit without any opens or breaks has continuity and needs no further testing. The jumper is usually a long wire with alligator clamps. A version of the jumper has a fuse holder in it with a 10amp fuse. This will prevent damaging the circuit if the jumper is connected in the wrong way. The jumper is used to locate opens in a circuit. One end of the jumper is attached to a voltage source and the other end is attached to the load in the circuit, i.e., lamps motor. If the load works, try “jumping” to circuit points that are progressively closer to the voltage supply. When the cir­ cuit load stops working, the open has been located. The jumper is also used to test components in the cir­ cuit such as connectors, switches, and suspected high resistance points. Unpowered Test Lamp This tool consists of a 12-volt lamp with leads. The ends of the leads usually have alligator clamps, but various kinds of probes, terminal spades, and special connectors also are used. The 12-volt test lamp continuity tester uses the vehicle’s battery to provide voltage to the circuit under test. 12 -volt testers are manufactured with a variety of tips, to permit touching them to connectors, bare wires, insulated wires or even wires within wiring harnesses. To check the tester before use, briefly touch the clip to one side of the battery and the probe to the other. 12-volt testers are NOT sensi­ tive to polarity in a circuit, and can be connected either way. The 12-volt test lamp generally has a sharp probe tip so it can be inserted into connector terminals or through the wire insulation for testing. It is important to keep the probe tip sharp to minimize the damage to wire insulation. When the test is complete at a particular point, be sure to tape any holes made in wire insulation. The unpowered test lamp is used on an open circuit. One lead of the test lamp is grounded and the other lead is moved around the circuit to find the open. Depending on the physical layout of the circuit, sometimes it will be easier to start at the voltage supply and other times it is easier to start at the circuit load or ground circuit. NOTICE: Test lamps are to be used only on circuits that do not contain solid state devices. If a test lamp is used in a circuit containing a solid state device, the current that the test lamp draws is above the current that the solid state device is able to handle. Using a test lamp on a solid state device may destroy the device. ____________ Meters Three types of meters are generally used for diagnosis. They are: 1 . The Ammeter. 2. The Ohmmeter. 3. The Voltmeter. Once one becomes familiar with the test lamp and the brilliance of the bulb in a normal circuit, high-resistance circuits can be recognized by the effect they have on the bulb. As the current drops in a high-resistance circuit, the bulb in the test lamp will glow less brightly. Although the 12-volt test lamp cannot be used as a foolproof test for high resistance, a less than normal brilliance of the lamp is an indication of circuit high resistance. Further testing will verify the condition and locate the cause. Powered Test Lamp This lamp is a pencil shaped unit with a self-contained battery, a 1.5 volt lamp bulb, a sharp probe and a ground lead fitted with an alligator clip. This test lamp is used mainly for testing components that are disconnected from the vehicle voltage supply. The powered test lamp is also useful for testing suspected high resistance points in a circuit such as connectors and ground circuits that are corroded or loose. NOTICE: The following instruments: Ammeter, Voltmeter, and Ohmmeter, each have a particu­ lar application for diagnosing electrical circuits. When using an ammeter or voltmeter, and the value being tested is unknown, always use the highest scale first and work downward to a midscale reading whenever possible. This will avoid damage to the instrument. Never use an ohmmeter in a voltage circuit, or as a substitute for a voltmeter or ammeter as damage to the instrument will result. These meters are available in two designs. They are: 1. Analog (Needle-Type). 2. Digital (Electronic Display-Type). CAUTION: The correct type of meter must be used when diagnosing circuits containing solid state devices. Incorrect use of the meters will result in damage to the solid state devices. Analog meters may be used for any circuit not containing a solid state device, while a digital meter MUST be used to diagnose any circuit with a solid state device. Circuits which contain a solid state device, such as the Electronic Con­ trol Module, should be tested only with a 10megaohm or higher impedance digital multimeter (J 29125 or equivalent). At normal operating voltage, most circuits have a char­ acteristic amount of current flow, referred to as normal current draw. Current draw is measured in amperes (amps) with an ammeter. Comparing measured current draw with the specified current draw rating provides use­ ful diagnostic information. Disconnect the circuit from the voltage source before connecting the ammeter. The ammeter (Figure 8) must be placed in series with the circuit being tested. Be sure that the ammeter’s positive terminal is connected to the posi­ tive (battery) side of the circuit and its negative terminal to the negative (ground) side of the circuit. CAUTION: Never connect an ammeter across a circuit like a voltmeter. The ammeter could be damaged by the vehicle electrical system. Excessive current draw is responsible for blowing fuses and, in some cases, draining the battery. An ammeter wiM help diagnose these conditions by locating the cause of the excessive current draw. On the other hand, there are times when a reduced current draw at a component (a power window motor for example) causes unsatisfactory performance of an electrical system. Ohmmeter (Figures 9 and 11) Ammeter (Figures 8 and 11) An ammeter is used to measure current flow (amper­ age) in a circuit. Amperes are units of electron flow which indicate how many electrons are passing through the cir­ cuit. Ohm’s Law indicates that current flow in a circuit is equal to the circuit voltage divided by total circuit resist­ ance. The ohmmeter is used to read resistance (ohms) or to check for opens or shorts in a circuit or component. There are both analog-type and digital-type ohmmeters. • An analog-type meter shows the actual resistance on a scale by the movement of a needle. • On a digital-type meter, the resistance measured is con­ verted inside the meter to a numerical output which is shown on a display panel. Ohmeters use a small battery to supply the voltage and current which flows through the circuit being tested. The current flows through the circuit, positions the needle on analog-type meters, or converts to a digital readout on digital-type meters. This is done in terms of resistance as shown in Ohm’s Law - R = E/I. Although there are several different styles of analog ohmmeters, all will usually have the following features in addition to the meter movement: • A range selector switch which permits the selection of different ranges of resistance. • A set adjust control which allows the meter to be set at zero for accurate measurements. • Some model ohmmeters also have a built-in feature that allows the ohmmeter to be used as a self-powered test lamp. 5 Digital meters do not have to be zeroed. They have vari­ ous ranges just like the analog meters. terminals, loose connections or other similar problems reduce the voltage available across the key circuit com­ ponents. The current flow is reduced in the circuit and all of the affected components operate at less than peak efficiency. A small drop across wires (conductors), switches, connectors, etc., is normal. (This is due to the resistance of the conductors but should be less than 10 percent of the total drop.) Voltmeter (Figures 10 and 11) The voltmeter (properly observed) will give the techni­ cian more information than the ammeter, ohmmeter and test lamp combined. Its application for diagnosis here is to measure the electrical pressure (voltage) drop in a resistance circuit (Figure 10). Voltage drop is a reduction or “using up” of the voltage to push electricity through a resistance. It can be compared to the pressure of water flowing through a metering valve. When using a voltmeter: • Be sure to connect the positive lead to the battery side and the negative lead to the ground side of the compo­ nent being checked. • Voltage drop occurs when electricity (current) flows through a resistance. Make sure the voltage drop being measured is only through the component being checked, not through the component and a poor con­ nection. • The circuit must be operating (lamp ON or motor run­ ning, for example) to measure voltage drop. CAUTION: Like a self-powered test lamp, the ohmmeter can only be used on circuits where voltage has been removed (Figure 9). It is designed to be operated on its own voltage sup­ ply. This voltage supply provides low voltage and current levels for the meter to make resistance measurements. The 12-volt electrical system volt­ age in the automotive circuits could damage the meter. Electrical circuits can be checked for opens using basi­ cally the same procedure as previously described for the self-powered test lamp. The circuit must be separated from all voltage sources. The ohmmeter is connected across the two open ends of the circuit to be checked. A high reading (infinity) is an indication of an open circuit. A low reading (near zero) is an indication of a continuous cir­ cuit. Checks for short circuits are made in a similar manner to that used for open circuits, except that the circuit being checked must be isolated from both voltage and normal ground. Connecting the ohmmeter between an isolated circuit and a good ground point will allow checking the circuit for shorts to ground. A short to ground in the circuit will be indicated on the meter by a near zero reading. A good circuit (no short to ground) will show up as infinity (very high resistance) indi­ cated on the meter. To measure the resistance of a component or a circuit, the component or circuit must be isolated from all other components (or circuits). The ohmmeter leads are then placed across the component or circuit and the resistance is read on the ohmmeter. 6 The instrument panel voltmeter (in the vehicle) should also be observed for monitoring proper operation of the generator, battery, cranking motor, and cranking circuit. In this application, battery voltage drop can be monitored while the engine is cranking; and after the engine is run­ ning, generator output voltage can be monitored. This can be a valuable first step before diagnosing other electrical problems. CIRCUIT WIRING REPAIR PROCEDURES Maintenance and Repair Low voltage to a lamp will make the lamp glow dimly. This can be caused by low source voltage (battery dis­ charge or low alternator output), or by high resistance in the circuit due to a poor connection. Before making any meter measurements, it is important to review the relation­ ship between current, voltage and resistance (Ohm’s Law). All electrical connections must be kept clean and tight. Loose or corroded connections may cause a discharged battery, difficult starting, dim lamps, and possible damage to the generator and regulator. Wires must be replaced if insulation becomes burned, cracked, or deteriorated. Always use rosin flux solder to splice a wire or repair one that is frayed or broken and use insulating tape to cover all splices or bare wires. Being able to determine voltage drop is important because it provides the following information: • Too high of a voltage drop indicates excessive resist­ ance. If, for instance, a blower motor runs too slowly or a lamp glows too dimly, one can be sure there is exces­ sive resistance in the circuit. By taking voltage drop readings in various parts of the circuit, the problem (corroded terminals) for example can be isolated. When replacing wire, it is important that the correct size wire be used as shown on applicable wiring diagrams or parts book. Each harness or wire must be held securely in place to prevent chafing or damage to the insulation due to vibration. Wire size in a circuit is determined by the amount of current, the length of the circuit and the voltage drop allowed. Wire size is specified using the metric gage. The metric gage describes the wire size directly in cross sec­ tion area measured in square millimeters. • Too low of a voltage drop, likewise, indicates low resist­ ance. If, for instance, a blower motor runs too fast, the problem could be isolated to a low resistance in a resis­ tor pack by taking voltage drop readings. • Maximum allowable voltage drop under a load is criti­ cal, especially if there is more than one high resistance problem in a circuit. It is important because like all resistances, all voltage drops are cumulative. Corroded Figure 11 — Meter Scales Wiring Connector Terminal Replacement (Blade-Type) CAUTION: Never replace a wire with one of a smaller size or replace a fusible link with a wire of a larger size. Remove or Disconnect (Figure 14) 1. Terminal lock tang. WIRE SIZE CONVERSION TABLE METRIC SIZE (mm)" AWG SIZE 0.22 0.35 0.5 0.8 1.0 2.0 3.0 5.0 8.0 13.0 19.0 32.0 40.0 50.0 62.0 24 22 20 18 16 14 12 10 8 6 4 2 1 0 00 2. Terminal (61). + 4- Install or Connect (Figure 15) 1. Pry up on the tang (70). 2. Terminal into the connector. Wire Repair The wire repair is very important for the continued reli­ able operation of the vehicle. This repair must be done as described in the following procedures. Figure 14 — Removing the Terminals from Twisted Wires/Shielded Cable (Figure 13) the Connector Remove or Disconnect Twisted Wires (Figure 12) Remove or Disconnect 1. Jacket (90). 1. Jacket (100). 107 2. Unwrap aluminum/myiar tape (101). 3. Drain wire (102). 4. Leads. 2. Twisted wires (91). 3. Insulation from the wire. 5. Insulation on the leads. +«- Install or Connect Install or Connect 1. Splice clip (92). 2. Crimp and solder the splice clips (93). 3. Electrical tape wrap (94) on the splices. 4. Outer jacket electrical tape wrap (95). 1. Splice clips (103). 2. Crimp and solder the splice clips (104). 3. Electrical tape wrap (105) on the splices. 100. 101. 102. 103. 104. 105. 106. Jacket A lum inum /M ylar Tape Drain Wire Splice Clip Crim p and Solder Electrical Tape Wrap Drain Wire Splice Clip, Crimped And Soldered. 107. O uter Electrical Tape Wrap 4. Aluminum/mylar tape by wrapping and taping. 5. Drain wire with a splice clip (106). Crimp and solder the splice clip. 6. Outer jacket electrical tape wrap (107). B-06231 Figure 13 — Twisted/Shielded Wire Repair Figure 15 — Resetting the Lock Tang 7 Wiring Connector Terminal Replacement (Twin Lock-Type) Remove or Disconnect (Figure 16) Tool Required: J 22727 Terminal Remover 1. Connector lock tangs (81). 2. Terminal locks using J 22727 (82). 3. Terminal (80). Install or Connect 1. Pry out the tangs. 2. Terminal (80) into the connector (81). Molded-on connectors require complete replacement of the connection. This means splicing a new connector assembly into the harness. Environmental connections cannot be replaced with standard connections. Instruc­ tions are provided with the Weather-Pack connector and terminal packages. With the low current and voltage levels found in some circuits, it is important that the best possible bond at all wire splices be made by soldering the splices. Use care when probing the connections or replacing terminals in them. It is possible to short between two ter­ minals. If this happens, it is possible that damage may be done to certain components. Always use jumper wires between connectors for circuit checking. Never probe through the Weather-Pack seals. When diagnosing for possible open circuits, it is often difficult to locate them by sight because oxidation or ter­ minal misalignment is hidden by the connectors. Merely wiggling a connector on a sensor or in the wiring harness may pinpoint the open circuit condition. This should always be considered when an open circuit is indicated while diagnosing. Intermittent problems may also be caused by oxidized or loose connections. METRI-PACK CONNECTORS The Metri-Pack connectors use a pull-to-seat type ter­ minal, as shown in Figure 17. The special tool required to remove the terminal is J 35689-A terminal remover. If removal is attempted with an ordinary pick, there is a good chance that the terminal will be bent or deformed. Refer to Figure 17. Weather-Pack Connector Replacement +«- Install or Connect (Figure 17) 1. Terminal insulator (134) on the wire. Slide the insulator back on the wire about 8 cm (3 inches). 2. Terminal (131) on the wire. • Roll crimp (132) and solder the terminal. 3. Terminal insulator (134) and the roll crimp (133). 4. Terminal into the connector. 5. Secondary lock (125). 6. Connector sections until the primary lock (121) engages. Metri-Pack Connector Replacement -►4- Tool Required: J 35689-A Terminal Remover 1. Primary lock (121) by lifting. 2. Connector body (137). 3. Connector seal (120) by pulling the seal back onto the wires away from the connector body (137). 4. Terminal (136) by inserting J 35689-A (139) into the connector body (137) to depress the locking tang (138), then push the wire and terminal through the connector body (Figure 17). • Snip off the old terminal unless the terminal is to be reused, reshape the locking tang. 5. 5 mm (0.2 inch) of the wire insulation (130). Remove or Disconnect (Figure 17) Tool Required: J 28742-A Terminal Remover (Figure 18) 1. Primary lock (121) by lifting. 2. Connector sections. WEATHER-PACK CONNECTORS Special connectors known as Weather-Pack connec­ tors (Figure 17) require a special tool J 28742-A (Figure 18) for servicing. This special tool is required to remove the pin and sleeve terminals. If removal is attempted with an ordinary pick, there is a good chance that the terminal will be bent or deformed. Unlike standard blade-type ter­ minals, these terminals cannot be straightened once they are bent. Make sure that the connectors are properly seated and all of the sealing rings ( 120) are in place when connecting the leads. The hinge-type flap (123) provides a back-up, or secondary locking feature for terminals. They are used to improve the connector reliability by retaining the terminals if the small terminal lock tangs (138) are not positioned properly. 8 Remove or Disconnect (Figure 17) Clean • Terminal cavity of the connector body. + 4- Install or Connect (Figure 17) 3. Secondary lock (125) by spreading the sides of the hasp, thus clearing the staples and rotating the hasp (127). 1. Terminal (136) on the wire. • Crimp and solder the terminal. 4. Terminal (136) by using J 287842-A (128, 139). • Snip off the old terminal assembly. 2. Terminal (136) into the connector cavity by pulling the wire on the seal side of the connector until the locking tang (138) is fully seated. 5. 5 mm of the wire insulation (130). Clean • Terminal Barrel (124). 3. Seal (120) by pressing the seal into the connector body (137) until it is fully seated. 4. Connector sections until the primary lock (121) engages. J 22727 1. Weather-Pack II Terminal Remover 2. Electrical Terminal Remover 3. Signal Generator and Instrument Panel Tester F-02438 Figure 18 — Special Tools 133 138 VIEW B 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. Connector Seal Primary Lock Secondary Lock Staple Secondary Lock Terminal Barrel Secondary Lock Lock Opened Lock Opened J 28742-A Terminal Remover Wire 130. 131. 132. 133. 134. 136. 137. 138. 139. 5 mm (0.2 inch) Terminal Roll Crimp Roll Crimp Terminal Insulator Metri-Pack Series 150 Female Terminal Connector Body Locking Tang J 35689-A Terminal Remover F -02349 Figure 17 — Weather-Pack and Metri-Pack Connectors 9 REGULAR PRODUCTION OPTION (RPO) LIST AU3 A31 B3D C36 C60 C65 C69 C7P D48 E63 K34 K68 LB4 LH6 LL4 L05 L19 M20 MD 8 MT1 MT 8 MY 6 NA1 NA4 R05 TP2 TR9 TVR T61 UJ1 UM 6 UM7 UY1 UY7 U89 V22 — Power Side Door Locks — Power Side Windows School Bus Equipment Auxiliary Heater Air Conditioning Auxiliary Air Conditioning Roof Mounted Air Conditioner — 16.000LB GVW Rating — Electric Remote Control Outside Mirror — Fleetside Body — Cruise Control — Generator-105 AMP — Engine, 4.3L (262 CID) V 6 Gasoline Engine, VIN Z — Engine, 6.2L (378 CID) V 8 Diesel Engine, VIN C — Engine, 6.2L (378 CID) V 8 HD Diesel Engine, VIN J — Engine, 5.7L (350 CID) V 8 Gasoline Engine, VIN K — Engine, 7.4L (454 CID) V 8 Gasoline Engine, VIN N — Man Trans, 4-Spd. — Auto Trans, 4-Spd., With Overdrive — Auto Tans, 5 Spd., With Overdrive — Man Trans, 5-Spd.. With Overdrive — Man Trans, 4-Spd. - Emission System, Less Than 8500 GVW — Emission System, Above 8500 GVW Dual Rear Wheels Auxiliary Battery Auxiliary Lighting Package Rear Dome and Reading Lamp Canadian Daytime Running Lamps Brake Warning Indicator System — Radio, ETR AM/FM Stereo, Cassette — Radio, ETR AM/FM Stereo, W/O Cassette Wiring Harness, Camper Truck Trailer Wiring Harness, HD Trailer Wiring Harness Quad Halogen Headlamps — ABBREVIATION LIST The following is a list of abbreviations used in the wiring diagrams. The abbreviations have been developed in such a way that their meaning should be clear. 10 Use this page as a reference to determine the meaning of an abbreviation if necessary. A -- Ampere A/C -- Air Conditioner AC -- Alternating Current ACC -- Accessory AIR -- Air Injection Reaction AIR/COND - Air Conditioner ALDL -- Assembly Line Diagnostic Link ALT - Alternator AMP -- Ampere ANTI - Anticipate ASM -- Assembly ASSY - Assembly AUD -- Audio AUTO -- Automatic AUX -- Auxiliary BAT -- Battery BATT -- Battery BI-LEV - Bi-Level BLK - Black BLT - Belt BLU -- Blue BOT - Bottom BRK - Brake BRN - Brown BU - Backup BUZZ - Buzzer CID -- Cubic Inch Displacement CIR/BRK - Circuit Breaker CIRC -- Circuit CLSTR - Cluster CNTRL -- Control COMP -- Compartment COMP -- Compressor CONN -- Connector CONV -- Convenience CTSY - Courtesy CYL - Cylinder DC -- Direct Current DEF - Defrost DK - Dark DIAG - Diagnostic DIM -- Dimmer DIR -- Directional RPO CODES AND ABBREVIATION LIST DISC - Discrete DIST - Distributor DIV - Diverter DM - Dome DR -- Door DRAC - Digital Ratio Adapter Controller DRL - Daytime Running Lamps ECM - Electronic Control Module EFE - Early Fuel Evaporation EGR - Exhaust Gas Recirculation ELEC -- Electric ENG - Engine EPR - Exhaust Pressure Regulator ESC -- Electronic Spark Control EST - Electronic Spark Timing ETR - Electronically Tuned Radio EVRV - Electronic Vacuum Regulator Valve EXC - Except LO - Low LP - Lamp LPS -- Lamps LT - Light LTR - Lighter M - Motor MAN - Manual MAP - Manifold Absolute Pressure MAX - Maximum MED - Medium MRKR - Marker MULT - Multiple NAT - Natural NEU - Neutral NO - Normally Open NC - Normally Closed ORN - Orange F-PUMP - Fuel Pump FLASH - Flasher FRT - Front 4WD - Four-Wheel Drive GEN GRA GRD GRN - Generator - Gray -- Ground -- Green HAND -- Handling HZ - Hazard HD -- Heavy Duty HD LP -- Headlamp HEI - High Energy Ignition HI - High HTR -- Heater IAC - Idle Air Control IGN - Ignition ILLUM - Illumination l/P -- Instrument Panel INC - Increased IND - Indicator INJ -- Injector INST - Instrument INTER -- Interior LD - Light Duty LH - Left Hand PK - Park PLR - Puller PNK - Pink PNL -- Panel PPL - Purple PRESS - Pressure PWR - Power RCVR - Receiver REF -- Reference RESIST - Resistance RH - Right Hand RPO - Regular Production Option RST - Rust RWAL - Real Wheel Antilock SEN - Sensor SEND - Sender SIG -- Signal SIL - Silver SKT - Socket SOL - Solenoid SPEEDO -- Speedometer STR - Stripe SW - Switch TACH - Tachometer TBI - Throttle Body Injection TCC -- Torque Converter Clutch TEMP -- Temperature TP -- Throttle Position T/L -- Tail Lamp TRANS -- Transmission TYP -- Typical V - Volt VAC -- Vacuum VLV - Valve VSS -- Vehicle Speed Sensor W/ -- With W/O -- Without W/S -- Windshield W WASHER -- Window Washer WDO -- Window WHT - White WGR -- Wiring YEL -- Yellow RPO CODES AND ABBREVIATION LIST 11 SECTION A R/V MODELS SECTION A A-1 LIGHTED VANITY MIRROR (SEE PAGE 119) ECM/PCM/TCM (SEE PAGES 59, 68, 72) RH TAIL, STOP AND TURN LAMPS (SEE PAGE 150) & BLOWER MOTOR (SEE PAGE 98) A-2 PHANTOM VIEW ROOF MARKER LAMPS (SEE PAGE 40) REAR A/C BLOWER (SEE PAGE 95) DOME LAMPS (SEE PAGE 119) RADIO (SEE PAGE 144) COURTESY LAMP (SEE PAGE 119) BATTERY (SEE PAGES 10, 12) RH HEADLAMP (SEE PAGES 25, 26, 32) LH REAR TAIL STOP AND TURN LAMPS (SEE PAGE 150) POWER DOOR LOCK ACTUATOR (SEE PAGES 131, 132, 134) AUXILIARY HEATER BLOWER (SEE PAGE 99) RH TURN LAMP (SEE PAGES 44, 46) WINDSHIELD WASHER MOTOR (SEE PAGE 52) HORNS (SEE PAGE 49) LH HEADLAMP (SEE PAGES 25, 26, 32) LH TURN LAMP (SEE PAGES 44, 46) LH SIDE MARKER LAMP (SEE PAGE 35) PHANTOM VIEW A-3 LIGHTED VANITY MIRROR (SEE PAGE 119) ECM/PCM/TCM (SEE PAGES 59, 68, 72) RH REAR TAIL, STOP AND TURN LAMP (SEE PAGE 150) POWER DOOR LOCK ACTUATOR (SEE PAGE 130) POWER WINDOW MOTOR (SEE PAGE 139) A-4 PHANTOM VIEW BLOWER MOTOR (SEE PAGE 98) DOME LAMP (SEE PAGE 119) RADIO (SEE PAGE 144) COURTESY LAMP (SEE PAGE 119) BATTERY (SEE PAGES 10, 12) RH HEADLAMP (SEE PAGES 25, 26, 32) LH REAR TAIL STOP AND TURN LAMPS (SEE PAGE 150) POWER DOOR LOCK ACTUATOR (SEE PAGES 131, 132, 134) RH TURN LAMP (SEE PAGES 44, 46) HORNS (SEE PAGE 49) LH HEADLAMP (SEE PAGES 25, 26, 32) LT TURN LAMP (SEE PAGES 44, 46) LH SIDE MARKER LAMP (SEE PAGE 35) PHANTOM VIEW A-5 LIGHTED VANITY MIRROR (SEE PAGE 119) ECM/PCM/TCM (SEE PAGES 59, 68, RH REAR TAIL, STOP AND TURN LAMPS (SEE PAGE 151) -6 PHANTOM VIEW RADIO (SEE PAGE 14) ROOF MARKER LAMPS (SEE PAGE 40) DOME LAMP (SEE PAGE 119) CARGO LAMP (SEE PAGE 120) FUEL TANK SENDING UNIT (SEE PAGES 77, 78, 79, 87, 88) COURTESY LAMP (SEE PAGE 119) BATTERY (SEE PAGES 10, 12) RH HEADLAMP (SEE PAGES 25, 26, 32) LH REAR TAIL, STOP AND TURN LAMPS (SEE PAGE 151) RH TURN LAMP (SEE PAGES 44, 46) POWER MIRROR WINDOW AND DOOR LOCK SWITCHES (SEE PAGES 129, 139) HORNS (SEE PAGE 49) LH HEADLAMP (SEE PAGES 25, 26, 32) LH TURN LAMP (SEE PAGE 44, 46) LH SIDE MARKER LAMP (SEE PAGE 35) WINDSHIELD WIPER MOTOR (SEE PAGE 52) PHANTOM VIEW A-7 SYMPTOMS INDEX SYMPTOM PAGE AIR CONDITIONING A/C compressor does not engage ...................................................................................................................... a -91 Blower motor does not operate in any m o d e ......................................................................................................A-92 Blower motor does not operate in H I .................................................................................................................... A-92 Blower motor does not operate in M E D ............................................................................................................... A-92 Blower motor does not operate in L O ......................................................................... ....................................... A-92 AIR CONDITIONING, Blower motor does Blower motor does Blower motor does REAR not operate at all ..................................................................................................................A-93 not operate in HI but only in LO ........................................................................................A-93 not operate in LO but only in HI ....................................................................................... ..A-93 AUDIO ALARMS Key-in warning alarm does not o p erate............................................................................................................... A-111 The safety belt warning buzzer does not operate ............................................................................................ A-111 The safety belt warning buzzer operates when safety belt is buckled........................................................... A-111 Lamps-on warning alarm does not o p e ra te ........................................................................................................A-111 AUXILIARY COOLING FAN Cooling fan does not run .......................................................................................................................................A-89 Cooling fan runs continuously............................................................................................................................... A-89 BRAKE SYSTEMS Brake indicator remains on with ignition switch in run and park brake o ff.................................................... A-114 Brake indicator does not light during a warning condition or during the antilock system check ............A-114 CRUISE CONTROL Cruise control does not disengage when clutch or brake pedal is depressed .......................................... A-122 Cruise control does not o p e ra te .......................................................................................................................... A-122 DIESEL ENGINE FUEL CONTROL Fuel heater does not o p e ra te ............................................................................................................................... A-86 Service fuel filter indicator lights with no water in fuel .....................................................................................A-86 Sen/ice fuel filter indicator does not light briefly with ignition switch turned to run ................................... A-86 TURN SIGNAL LAMPS Turn signals do not work on one s id e .................................................................................................................A-42 Turn signals do not operate ................................................................................................................................. A-43 Turn signal lamps flash ra p id ly ............................................................................................................................ A-43 FRONT PARK, MARKER, ROOF AND HAZARD LAMPS Front park and side marker lamps do not operate............................................................................................A-33 Roof marker lamps do not o p e ra te ..................................................................................................................... A-33 Hazard warning lamps do ont operate .............................................................................................................. A-33 FOUR-WHEEL DRIVE INDICATOR LAMPS Four-wheel drive indicator lamp will not turn o ff................................................................................................ A-125 Four-wheel drive engages but 4WD indicator lamp does not light (V100, V 2 0 0 ) ........................................ A-125 Four-wheel drive engages but 4WD indicator lamp does not light (V 3 0 0 )....................................................A-125 A-8 SYMPTOM INDEX HEADLAMPS Headlamps do not illuminate high or low beams -- both s id e s ......................................................................a -23 Low beam lamp(s) do not operate .....................................................................................................................a -23 High beam lamps(s) do not o p e ra te .................................................................................................................. a -24 Daytime running lamps do not operate (Canada o n ly ).................................................................................... a -24 Daytime running lamps stay on (Canada only) ............................................................................................... a -24 HEATER, FRONT Blower motor does not operate at all ................................................................................................................ a -96 Blower motor does not operate in HI but only in LO and/or M E D ................................................................. a -96 Blower motor does not operate in LO and/or MED but only in H I ................................................................. a -96 HEATER, AUXILIARY Auxiliary heater blower motor does not operate at all ....................................................................................a -96 Auxiliary heater blower motor does not operate in L O .................................................................................... a -96 HORNS Horn(s) will not operate ....................................................................................................................................... a -48 Horn sounds continuously without depressing horn switch .......................................................................... a -48 Cigarette lighter does not operate....................................................................................................................... a -48 INSTRUMENT PANEL: GAGES AND INDICATORS Fuel gage indicates full or beyond at all tim es..................................................................................................A-100 Fuel gage indicates empty when there is fuel in the ta n k ............................................................................... A-100 Fuel gage is inaccurate ....................................................................................................................................... A-100 Temperature gage indicates hot with engine coolant below operating temperature and ignition switch in R U N ................................................................................................................................ A-101 Temperature gage indicates cold all the time .................................................................................................. a -101 Temperature gage is not accurate .....................................................................................................................A-101 Oil pressure gage indicates low pressure when oil pressure is g o o d .......................................................... A-101 Oil pressure gage indicates high pressure at all tim es....................................................................................A-101 Oil pressure gage is not accurate....................................................................................................................... A-101 Voltmeter is not accurate ..................................................................................................................................... A-101 Speedometer is inoperative or inaccurate......................................................................................................... A-102 Low coolant indicator does not light with coolant level low (diesel only)......................................................A-102 Low coolant indicator is lit when coolant level is g o o d ....................................................................................A-102 COURTESY LAMPS,CARGO LAMPS AND UNDERHOOD LAMP Courtesy lamps do not operate............................................................................................................................A-118 Dome lamp does not work or stays on all the time .........................................................................................A-118 Cargo lamp does not w o r k ...................................................................................................................................A-118 l/P compartment box lamp does not w o rk ......................................................................................................... A-118 UnderhOod lamp does not w o rk ......................................................................................................................... A-118 POWER DOOR LOCKS (WITH SWING OUT SIDE DOOR) None of the door lock motors lock or u n lo c k .................................................................................................... A-128 One door lock motor does not lock or unlock from a particular switch........................................................ A-128 One door lock motor does not operate from any switch ............................................................................... A-128 No door lock motors lock or unlock from any switches ................................................................................. A-128 POWER WINDOWS Power windows does not operate or only go in one direction ......................................................................A-136 Power windows only operate from driver’s side window switch ................................................................... A-137 Power windows do not operate from driver’s side window switch................................................................. A-137 Tailgate window does not operate from tailgate window s w itc h ................................................................... A-137 Tailgate window does not operate from key operated tailgate window switch.............................................A-138 GLOW PLUGS Wait indicator does not flash or flashes for the incorrect amount of time when engine is below normal operating tem perature............................................................................................................................ A-82 Wait indicator stays on or flashes when engine is at normal operating temperature and ignition switch in run position (6.2L diesel engine) ..................................................................................................... A-83 HEADLAMPS Headlamps do not illuminate high or low beams - both s id e s .......................................................................A-23 Low beam lamp(s) do not operate ..................................................................................................................... A-23 High beam lamps(s) do not o p e ra te ...................................................................................................................A-24 Daytime running lamps do not operate (Canada o n ly ).....................................................................................A-24 Daytime running lamps stay on (Canada only) ................................................................................................ A-24 HEATER, FRONT Blower motor does not operate at all ................................................................................................................ A-96 Blower motor does not operate in HI but only in LO and/or M E D ..................................................................A-96 Blower motor does not operate in LO and/or MED but only in H I ..................................................................A-96 HEATER, AUXILIARY Auxiliary heater blower motor does not operate at all .....................................................................................A-96 Auxiliary heater blower motor does not operate in L O .....................................................................................A-96 HORNS Horn(s) will not operate ....................................................................................................................................... A-48 Horn sounds continuously without depressing horn switch ........................................................................... A-48 Cigarette lighter does not operate....................................................................................................................... A-48 INSTRUMENT PANEL: GAGES AND INDICATORS Fuel gage indicates full or beyond at all tim es...................................................................................................A-100 Fuel gage indicates empty when there is fuel in the ta n k ................................................................................A-100 Fuel gage is inaccurate ....................................................................................................................................... A-100 Temperature gage indicates hot with engine coolant below operating temperature and ignition switch in R U N ................................................................................................................................ A-101 Temperature gage indicates cold all the time ...................................................................................................A-101 Temperature gage is not accurate ..................................................................................................................... A-101 Oil pressure gage indicates low pressure when oil pressure is g o o d ...........................................................A-101 Oil pressure gage indicates high pressure at all tim e s .....................................................................................A-101 Oil pressure gage is not accurate....................................................................................................................... A-101 Voltmeter is not accurate ..................................................................................................................................... A-101 Speedometer is inoperative or inaccurate......................................................................................................... A-102 Low coolant indicator does not light with coolant level low (diesel o n ly )...................................................... A-102 Low coolant indicator is lit when coolant level is g o o d .....................................................................................A-102 COURTESY LAMPS,CARGO LAMPS AND UNDERHOOD LAMP Courtesy lamps do not operate............................................................................................................................A-118 Dome lamp does not work or stays on all the time ......................................................................................... A-118 Cargo lamp does not w o r k ...................................................................................................................................A-118 l/P compartment box lamp does not w o rk ......................................................................................................... A-118 UnderhOod lamp does not w o rk ......................................................................................................................... A-118 POWER DOOR LOCKS (WITH SWING OUT SIDE DOOR) None of the door lock motors lock or unlock..................................................................................................... A-128 One door lock motor does not lock or unlock from a particular sw itch........................................................ A-128 One door lock motor does not operate from any switch ................................................................................A-128 No door lock motors lock or unlock from any switches .................................................................................. A-128 POWER WINDOWS Power windows do not operate or only go in one direction ......................................................................... A-136 Power windows only operate from driver’s side window switch .....................................................................A-137 Power windows do not operate from driver’s side window switch.................................................................. A-137 Tailgate window does not operate from tailgate window s w itc h .....................................................................A-137 Tailgate window does not operate from key operated tailgate window switch............................................. A-138 POWER MIRRORS Neither mirror is operational ..................................................................................................................................A-127 LH mirror will not adjust UP and DOWN .............................................................................................................A-127 LH mirror will not adjust LEFT and R IG H T .......................................................................................................... A-127 RH mirror will not adjust UP and DOWN .............................................................................................................A-128 RH mirror will not adjust LEFT and R IG H T.......................................................................................................... A-128 SYM PTOM PAGE AM RADIO Radio does not appear to work (no display lights, no sound) .......................................................................A-143 Clock does not operate .........................................................................................................................................A-143 Panel lamp does not come on .............................................................................................................................A-143 Display dimming function will not o p e ra te .......................................................................................................... A-143 No sound or distorted sound from a speaker ................................................................................................... A-143 REAR DEFOGGER Rear window defogger does not work and on indicator does not lig h t........................................................ A-146 On indicator works but rear window defogger does not defrost.................................................................... A-146 Rear defogger panel lamp does not w o r k ..........................................................................................................A-146 REAR EXTERIOR LAMPS Backup lamps do not operate............................................................................................................................... A-149 Rear park, marker and license lamps do not operate .....................................................................................A-149 START AND CHARGE Engine does not crank and starter solenoid does not click ........................................................................... A-53 Starter solenoid clicks, engine does not crank or cranks slowly.................................................................... A-54 Battery is undercharged or overcharged...................................................................... - .................................. A-54 VACUUM SYSTEMS Little or no heat from auxiliary heater .................................................................................................................A-161 Improper air distribution from outlets................................................................................................................... A-161 Cruise control does not o p e ra te .......................................................................................................................... A-161 WINDSHIELD WIPERS AND WASHERS (PULSE) Wipers do not operate in any mode ................................................................................................................... A-50 Wipers do not operate in HI ................................................................................................................................. A-50 Wipers do not operate in LO or d e la y ................................................................................................................ A-50 Washer motor does not o p e ra te ..........................................................................................................................A-51 Washer motor does not shut o f f .......................................................................................................................... A-51 SYMPTOM INDEX A-9 RPO CODES - AIR CONDITIONING ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N ■GENERATOR-105 AMP - AUTO TRANS, 4-SPD., WITH OVERDRIVE - MAN TRANS, 4-SPD - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE AUXILIARY BATTERY - WIRING HARNESS, CAMPER • TRUCK TRAILER WIRING HARNESS, HD 1-32.0 BLK I I I 150*8.0 BLK I 4“ dcm o 55 CO p — AUXILIARY BATTERY .2-1.0 R S T ---"(FUSIBLE LIN K)1 AUXILIARY COOLING FAN RELAY (L19 AND C60) S105 o (SEE PAGE 90) AUXILIARY BATTERY JUNCTION BLOCK hi CC BATTERY JUNCTION BLOCK (TP2) S118 • I 2-8.0 RED I I § w CM I g 3 IN-LINE FUSE 30 AMP j • \ 1 ^ 1 ^ - 1 2 - 5 . 0 RED S103 I J I I CC CO I I mm I I-Hi O(/> i 2-5.0 RED CO - I CC £Q —0 fUJ (O -I CC CD CM j A/C TRANSMISSION CONNECTOR ♦ (SEE PAGE S C172 © CO C3P 12084690 I CAMPER AND TRAILER I WIRING (SEE PAGE 160) 0 H i 2-8.0 RED ■ ■ S104 I AUXILIARY BATTERY RELAY C106 12045896 (TP2) I ________ GENERATOR I 6-3.0 PPL I 1-32.0 BLK STARTER MOTOR A-10 POWER DISTRIBUTION GASOLINE ENGINE SHEET METAL GROUND G111 ENGINE GROUND G112 SHEET METAL GROUND G109 vj T++1++ - --------- H k\ '------- —^ --------- fcH k ■ >h |t J < Hi ■m • ■ T t .. -------' H I D RPO CODES LH6 • ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J M20 * MAN TRANS, 4-SPD MT1 - AUTO TRANS, HD, 4-SPD. WITH OVERDRIVE UY7 - TRUCK TRAILER WIRING HARNESS, HD COLD ADVANCE TIMER RELAY (LH6 ONLY) (SEE PAGE 64) \ ■ 1-32.0 BLK I --------1-------- I1 3.0 B L K ^ H " ■ M M K | 1-32.0 BLK M H H ® COLD ADVANCE FAST IDLE TEMPERATURE SWITCH (SEE PAGE 87) 9 FUEL HEATER (SEE PAGE 87) ' WATER IN FUEL SENSOR (SEE PAGE 87) RH BATTERY 1 39-.8 PNK/BLK I I 39-.8 PNK/BLK I 3S-.8 PNK/BLK r I 39-.S PNK/BLK I 1 39-.S PNK/BLK I l 39-.8 PNK/BLK I EGR DUMP (LH6 o n ly ) (SEE PAGE 64) i mmm EPR SOLENOID (LH6 ONLY) (SEE PAGE 64) EGR SOLENOID PULSE WITH MODULATION (LH6 ONLY) (SEE PAGE 64) FUEL SHUTOFF SOLENOID (SEE PAGES 87, 88) S109 GENERATOR C — n^ M 1 > r — • ---- i / !I1 T \11t > —-n--- I X 9 0 6 -.5 G R A ^ B B (FUSIBLE LINK) 0106 12045896 Hi -m -m 5- ENGINE • • L r r m 2-3.0 RED I STARTER MOTOR I 2-3.0 RED I I 2-1.0 RST I (FUSIBLE LINK) I 6-3.0 PPL I BATTERY JUNCTION BLOCK / 13-3.0 P N K * i (LL4 ONLY) sios / 12-1.0 RST1 (FUSIBLE LINK) i 906-1.0 PPL E I 2-3.0 RED I S106 12-8.0 BLK/REDI 1 LEFT BANK GLOW PLUGS GROUND G113 & 1 RIGHT BANK GLOW PLUGS GROUND G114 SHEET METAL GROUND G111 A-12 POWER DISTRIBUTION D1ESEJLEN G IN E3_ C119 A/C i 2-5.0 R E D i * 1906-1.0 PPL S121 (LH6 ONLY) S130 (LL4 ONLY) (SEE PAGE 94) ■ 531-.8 LT GRN/BLK (LH6 ONLY)« 12-5.0 DK BLU/WHT I IN-LINE FUSE 30 AMP .* 5 3 1 - .8 LT G RN/BLKI I 531-.8 LT GRN/BLK COLD ADVANCE CONTROL (LH6 ONLY) (SEE PAGE 64) 13-3.0 PNK * FUEL SOLENOID (LL4 ONLY) (SEE PAGES 87, 88) 3*3.0 PNK (LL4 ONLY) TRAILER WIRING (SEE PAGE 160) GLOW PLUG CONTROLLER C168 12015982 COLD ADVANCE TIMER REL/Y (LH6 ONLY) (SEE PAGE) COWL RPO CODES LH6 - ENGINE, 6.2L <378 CID) VS DIESEL ENGINE, VIN C LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE POWER CIRCUIT 76 30-A M P CIRCUIT BREAKER AUTO TRANS/CONV CLUTCH M D 8 DIESEL ONLY TAIL GATE POWER WINDOW POWER WINDOW S NOTE: L U ENGINES DO NOT USE THE CRANK, ECM I OR ECM B FUSES. LH6 ENGINES DO NOT USE THE CRANK FUSE NOTE: DRL ARE ONLY ON VEHICLES FOR SALE IN CANADA WITH T61. AUXILIARY BATTERY FOUR WHEEL DRIVE ILL LP PANEL LAMPS REAR DEFOGGER REAR DEFOGGER LAMP CRUISE CONTROL FOUR-WHEEL DRIVE IND. LP DIESEL AUXILIARY FUEL TANK SELECTOR SWITCH POWER CIRCUIT 6 0 30-A M P CIRCUIT BREAKER REAR HEATER TAIL GATE-POWER W INDOW CLOCK REAR A/C REAR DEFOGGER 2 5 0 -3 .0 B R N -A U X HEATER A/C DOME & -CARGO LAMP POWER LOCKS 43-1.0 YEL - RADIO 250-3.0 BRN AUX HEATER A/C 7 6 -3 .0 PNK —IGN PWR W D O - 8 .5 GRA —INSTRUMENT LPS 2 4 0 -1 .0 O R N -B A T T FUSED HORN/DM 4 4 -1 .0 DK GRN —LT SW RHEOSTAT 1 2 0 4 1 2 3 5 SHUNT 2 5 0 -3 .0 B R N -A U X HEATER A/C T U R N B /U PW RW DO W IPE R GiO K ] ECM i 2 3 .0 R ED -B ATTER Y 1 4 0 . 8 O R N -H A Z A R D FLASHER 3 0 0 -3 .0 ORN —IGNITION 4 3 -1 .0 Y E L -R A D IO 4 3 -.5 YEL—RADIO o DR L D3 0 0 1 D) CRANK ------------------ — \ / v ___ / 3 -3 .0 P N K -IG N SW —ENG-IGN 39-.8 PNK/BLK - IGN - ON AND CRANK - FUSED 4 0 .8 ORN —TAIL LPS/CTSY LPS/PARK LPS 5 0 -2 .0 B RN -HEA TER A/C 2 -3 .0 R E D -IG N S W -B A T T 440 .8 ORN - ECM B 3 8 .8 DK B L U -D IR SIG FLASHER--------- 4 3 .0 BRN —IGNITION S W -A C C 9 3 - 8 W H T - W /S WASHER 9 3 .8 W H T - W /S WASHER 7 5 - 8 DK B LU -BACKUP LP SW 4 3 9 .8 PNK/BLK-ECM-FUSED 16 .8 PPL —DIRECT SIG SW FRONT 1 2 0 3 4 3 5 9 BLOCK MOLD 1 2 0 5 9 4 5 2 PRINTED BLOCK CAUTION: Determine If non-cycling circuit breakers are hot before removing them. Hot non-cycling circuit breakers can cause personal injury. A B C D E W F A-14 FUSE BLOCK COLOR MALE CONN NAT BRN BLK GRN RED BLU DK GRA 12004888 12004887 12004886 12004885 12004883 12004884 12004740 3 -3 .0 PNK —IGN 1 ■38 .8 DK BLU —DIRECT SIG FUSE 340-.8 ORN DRL 2-3.0 RED - BATTERY 6 3 .0 PPL-STARTER SOLENOID FEED 8 0 6 .8 PPL/WHT—ECM CRANK FUSED 7 6 -3 .0 P N K -IG N PWR W D O ---------------- REAR LAMP BULB DATA AC Type Guide Lamps are recommended when replacement becomes necessary. Lamp Usage FUSE AND CIRCUIT BREAKER IDENTIFICATION 6025 H6054 (Opt.) 66/65 35/65 (4) Headlamp System - Lo - HI 2 2 2 H4703 H4701 55 65 H4651 (Opt.) 50 Dome Lamps 2 211-2 12 Instrument Cluster Lamps 5 168 3 1 2 1 4** 168 3 2057 2-32 67 4 3057NA 1.5-24 Turn Signal Indicator Lamp 2 168 3 Park Lamps (W/4 Headlamps) 194NA 1.5 194 2 Rear Side Marker Lamps 2 2 2 168 3 Roof Marker Lamps 5 194 2 Brake Warning Indicator Cargo Lamp* 1 2 1 1 RADIO AUXILIARY BATTERY RELAY FOUR-WHEEL DRIVE INDICATOR LAMP AUTOMATIC TRANSMISSION CONVERTER CLUTCH (MD8 ONLY) Fender Clearance Lamp* Rear Identification* Radio Dial Lamp Four-Wheel Drive Indicator COLOR AND AMPERE HOT CONDITION AUX HTR A/C 12004010 WHITE 25 AMP HOT IN RUN AUXILIARY HEATER AND AIR CONDITIONING CRANK 12004003 VIOLET 3 AMP HOT IN START ECM CRANK CIRCUIT DRL 12004008 LTBLU 15 AMP HOT AT ALL TIMES RED 10 AMP HOT IN RUN OR START ECM B 12004007 RED 10 AMP HOT AT ALL TIMES GAGE/IDLE 12004009 YELLOW 20 AMP HOT IN RUN OR START HORN/DM 12004009 YEL 20 AMP HOT AT ALL TIMES HTR A/C 12004010 WHITE 20 AMP HOT IN RUN IGN 12004009 YELLOW 20 AMP HOT IN RUN OR START INST LPS PWR ACC PWR WDO RADIO 12004005 (CIRCUIT BREAKER) DRL ECM 1 ECM IGNITION CRANK HORN DOME AND CARGO LAMPS CLOCK REAR DEFOGGER CRUISE CONTROL DIESEL AUXILIARY FUEL TANK SELECTOR SWITCH HOT W/LIQHT SWITCH IN HEAD OR PARK INSTRUMENT PANEL LAMPS 30 AMP HOT AT ALL TIMES TAIL GATE POWER WINDOW REAR DEFOGGER POWER LOCKS 30 AMP HOT IN FUN 12004008 LT BLUE 15 AMP HOT IN ACC OR RUN Candle Power Headlamp Beam Indicator Lamp Taillamp and Stoplamp1 License Lamp Turn Signal (Front Park Lamps)1 HEATER AND AIR CONDITIONING TAN 5 AMP (CIRCUIT BREAKER) POWER WINDOWS Front Side Marker Lamps Backup Lamp Heater or A/C Control STOP HAZ 12004008 LTBLU 15 AMP HOT AT ALL TIMES HAZARD FLASHER T/L CTSY 12004009 YELLOW 20 AMP HOT AT ALL TIMES TAILLAMPS COURTESY LAMPS PARKING LAMPS Low Coolant Lamp2 TURN SIGNALS BACKUP LAMPS Safety Belt Warning WINDSHIELD WIPERS Glow Plugs Indicator2 TURN/BU 12004008 LT BLUE 15 AMP HOT IN RUN OR START WIPER 12004010 WHITE 25 AMP HOT IN ACC OR RUN Power Rating at 12V, Watts 2 2 FUSE PART NO. 12004007 Trade No. Headlamps (2) Headlamp System DESCRIPTION FUSE LOCATION ECM 1 Quantity Courtesy Lamp Clock Four-Wheel Drive Shift Lever Water In Fuel2 “SERVICE ENGINE SOON" Lamp (W/Gasoline Engine) (W/LH6 Diesel) Underhood Lamp Reading Lamp 168 3 1156 32 194 1142 2 21 4 168 3 5 Part of Lens 3 1 1 1 1 1 1 1 1 1 1893 161 2 1 1003 15 194 2 168 3 168 3 194 194 2 2 2 1 1 1 2 194 1893 2 2 19/10 9.9 906 6 194 2. Diesel only. * Not used on Suburban and Utility. ** 2 Required with 4 headlamp system. BULB DATA AND FUSE BLOCK A-15 £ — ■+■ *— jn __ H~ I150-.8 BLK I AUXILIARY BATTERY BATTERY A/C COMPRESSOR (L19) (SEE PAGE 94) ECM/PCM I 551 -.8 TAN/BLK ■ 3 CD [ (FLEETSIDE, WIDESIDE, STEPSIDEJ (SEE PAGE 59) LH PARK AND TURN LAMP A/22) I 150-.8 BLK (SEE PAGE 35) LH PARK LAMP (V22) (SEE PAGE 35) 150-.8 BLK 1150-.8 BLK I RWAL (W/O C60) (SEE PAGE 116) I 1-32.0 BLK I S113 RH HIGH-LOW HEADLAMP 151-.8 BLK I I 150-.8 BLK I (SEE PAGE 25) 151-.8 BLK I RWAL (W/C80) (SEEPAGE 116) RH PARK AND TURN LAMP (SEE PAGE 34) r L • ■ ■ ■ 150-.8 BLK LH LOW BEAM HEADLAMP (V22) (SEE PAGE 32) 150-.8 BLK LH HIGH BEAM HEADLAMP (V22) (SEE PAGE 32) RH PARK LAMP (SEE PAGE 35) 151-.8 BLK LH PARK AND TURN LAMP (SEE PAGE 34) I 150-.8 BLK AUXILIARY ENGINE COOLING FAN (L19 WITH C60) 151-2.0 BLK« 551-.8 TAN/WHTr ECM/PCM (W/O C60) (SEE PAGE 68) (SEE PAGE 90) • S122 LH HIGH-LOW HEADLAMP (SEE PAGE 25) \ 150-.8 BLK S111 RH HIGH BEAM HEADLAMP (V22) 151-.8BLK *- j tu (SEE PAGE 32) RH LOW BEAM HEADLAMP (V22) (SEE PAGE 32) 151-.8 BLK I 150-.8 BLK I LH PARK LAMP (SEE PAGE 34) I 151-3.0 8LK G107 G106 SHEET METAL GROUND FRAME GROUND A-16 GROUND DISTRIBUTION GASOLINE ENGINE V G109 G112 ENGINE GROUND SHEET METAL GROUND / 1 G105 ENGINE GROUND RPO CODES L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N M20 - MAN TRANS, 4-SPD. C60 - AIR CONDITIONING V22 - QUAD HALOGEN HEADLAMPS MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE C200 ECM/PCM 1413- 8 TAN DRL MODULE (SEE PAGE 26) 150-.8 BLK I (SEE PAGES 59, 68) (M20 ONLY) . (M20 ONLY) 450-.8 BLK/WHT | 450- 8 BLK/WHT I LIGHT SWITCH 150-.8 BLK I (SEE PAGE 25) Mmm ^m m r 450-.8 BLK/WHT « T 450-.8 b lk /w h T 419/450 i FUEL PUMP RELAY f 450-.8 BLK/WHT* HEATER CONTROL LAMP (SEEPAGE 110) 150-.8 BLK I (SEE PAGE 60) 4 450-.8 BLK/WHT *m m r *m m r mmm* RADIO 1S0-.8 BLK ' I 450-.8 BLK/WHT 1 (SEE PAGE 144, 145) \ ECM/PCM (SEE PAGE 59) WINDSHIELD WIPER SWITCH S117 150-.8 BLK I (SEE PAGE 59) 450-.8 BLK/WHT I 486-.8 BRN I r ECM/PCM 450-.8 BLK/WHT EVRV (SEE PAGE 60) ESC HYBRID MODULE S215 !• w/ 450-.8 BLK/WHT (SEE PAGE 79) 450-.8 BLK/WHT <\ FUEL PUMP CYCLE RELAY (SEE PAGE 52) S201 ALDL (SEE PAGE 59) l/P CLUSTER (SEE PAGE 107) 150-.8 BLK I DRAC 450-.8 BLK/WHT [ (SEE PAGE 75) (SEE PAGE 58) Z < 150-.8 BLK I _______ 450-.8 BLK/WHT PARK/NEUTRAL SWITCH (L05 WITH MD8) (SEE PAGE 59) l _ r 1150:. 8 BLK m 150:.8BLK ^ CONVENIENCE CENTER (SEE PAGE 21) SAFETY BELT RETRACTOR SWITCH (SEEPAGE 112) ENGINE GROUND DASH PANEL GROUND I G200 IIP GROUND GROUND DISTRIBUTION A-17 GASOLINE ENGINE i— i - 4 1*32.0 BLK I n n n — “h LH BATTERY -h RH BATTERY TCM (LL4 WITH MT1) (SEE PAGE 72) 1-32.0 BLK FUEL HEATER (SEE PAGE 87) 5 1-.8 B LK I 151-.8 BLK | RH HIGH-LOW HEADLAMP (SEE PAGE 25) WATER IN FUEL SENSOR (SEE PAGE 87) RH PARK AND TURN LAMP (SEE PAGE 34) 151-.8 BLK I RH PARK LAMP (SEE PAGE 34) 151-.8 BLK I RH HIGH BEAM HEADLAMP (V22) (SEE PAGE 32} 151-.6 BLK I RH LOW BEAM HEADLAMP (V22) (SEE PAGE 32) W/O C60 151-3.0 BLK 1 SHEET METAL GROUND FRAME GROUND A-18 GROUND DISTRIBUTION DIESEL ENGINES G114 G107 y i G113 0 12020183 C100 RIGHT BANK GLOW PLUG GROUND LEFT BANK GLOW PLUG GROUND ENGINE GROUND RPO CODES LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE V22 - QUAD HALOGEN HEADLAMPS 1151-.8 BLK (LH6 ONLY)l ALDL (SEE PAGE 63) ■150-.8 BLK I ALDL (LL4 ONLY) (SEE PAGE 73) ■150-.8 BLK I WINDSHIELD WIPER SWITCH (SEE PAGE 52) 1150-.8 BLK 1 DRL MODULE (SEE PAGE 26) I150-.8 BLK I CHECK ENGINE LAMP DRIVER MODULE (LH6 ONLY) (SEE PAGE 105) HEATER CONTROL LAMP (SEE PAGE 110) 1150*.8 BLK I LOW COOLANT WARNING MODULE (SEE PAGE 106) 1150-.8 BLK I RADIO (SEE PAGES 144, 145) GLOW PLUG LAMP (SEE PAGE 105) l/P CLUSTER 1150-. 8 BLK I (SEE PAGE 107) K150-.8BLKI 1150-.8 BLK I DRAC MODULE (LL4 ONLY) (SEE PAGE 75) I150-.8 BLK CONVENIENCE CENTER (SEE PAGE 21) SAFETY BELT RETRACTOR SWITCH (SEE PAGE 112) COPPER BRAID ■ „ , G200 i/p ■=■ GROUND CO) G102 ENGINE GROUND __ G103 DASHPANEL GRAND GROUND DISTRIBUTION A-19 DIESEL ENGINES RPO CODES R05 - DUAL REAR WHEELS 1150-.8 BLK I 1150-. 8 BLK I 1150-.8 BLK I 1150*.8 BLK I I150-.8 BLK | LH FRONT AND REAR CLEARANCE LAMPS (R05) (SEE PAGE 157) RH FRONT AND CLEARANCE LAMPS (R05) (SEE PAGE 157) I 150-.8 BLK I LH SIDE MARKER LAMP (SEE PAGE 156) I 150-.8 BLK I RH SIDE MARKER LAMP (SEE PAGE 156) LH BACKUP LAMP (SEE PAGE 153) I150-.8 BLK 1 RH BACKUP LAMP (SEE PAGE 153) LH TAIL, STOP AND TURN LAMP (SEE PAGE 150) 1150-.8 BLK I RH TAIL, STOP AND TURN LAMP (SEE PAGE 150) I 150-.8 BLK I 1150-.8 BLK I (FLEETSIDE, WIOESIDE ONLY) 1150-.8 BLK I S402 G402 G403 G406 SHEET METAL GROUND SHEET METAL GROUND LH TAIL, STOP, AND TURN LAMP GROUND G405 FRAME GROUND FLEETSIDE, WIDESIDE, SUBURBAN AND UTILITY STEPSIDE A-20 GROUND DISTRIBUTION REAR LAMPS G407 RH TAIL, STOP, AND TURN LAMP GROUND AUDIO ALARM 238. SAFETY BELT RETRACTOR SWITCH 150' GROUND 237' SAFETY BELT INDICATOR LAMP 39' 80' 140' 8' KEY IN SWITCH (SEE PAGE 113) IGNITION STOP HAZ FUSE (SEE PAGE 36) I 80-.5 LT GRN KEY IN SWITCH BATTERY LIGHTS ON SWITCH INSTR LPS (SEE PAGE 110) GAGE/IDLE FUSE (SEE PAGE 26) INSTRUMENT PANEL (SEE PAGE 105) SAFETY BELT RETRACTOR SWITCH (SEE PAGE 112) 39-.S PNK/BLK I 237-.8 YEL HORNS (SEE PAGE 49) HORN/DM FUSE (SEE PAGE 49) HORN RELAY CIGARETTE LIGHTER (SEE PAGE 49) HAZARD FLASHER SWITCH (SEE PAGE 36) I 27-.8 BRN HORN SWITCH (SEE PAGE 49) CONVENIENCE CENTER D U HAZARD FLASHER (Q ) ■=" l/P GROUND G200 CONVENIENCE CENTER A-21 RPO CODES TP2 - AUXILIARY BATTERY 1-32.0 BLK + £ o o - GT 105 8911214 BATTERY I I 141-.8 BRN/WHT 11 £■ z CC m I AUXILIARY BATTERY RELAY t^BAT-t (cj (g (Aj ® b HTR i IS ¥ 1T11V11 VrTa1 V11Tni i' y1 m [D] U m ® in ® m / WDO [c ] [c ] ra ra no Ei tu M gnJ SHUNT SHUNT ° ACC LPS PWR 30 ii » 4 A n i | u M L s in i In i ii INSTR LPS PWR ACC iL s Ik 0 i p l a m BIGN__AUX_HTR d B 3* “ D dHAi ................... .. _A/C STOP HAZ 20AJ j^25A^ | T/L CTSY GAGE/tDLE H TR A/d S105 • ECM B S118 I■ ■ ■ I 2-8.0 RED ■ 2-8.0 RED ■ ■ TURN B/U PWR WDO I 15A r~15A L kS I k 0 ( kS _RADlO RADIO W3 I k fi I kS KWIPERl a ^ ECM 1 150-8.0 BLK K J DRL 0 □ 0 B^S □ □ REAR FUSE BLOCK 12103404 w SHEET METAL GROUND G111 A-22 AUXILIARY BATTERY AUXILIARY BATTERY SHEET METAL GROUND G109 AUXILIARY BATTERY JUNCTION BLOCK SHEET METAL GROUND G108 o' | CIRCUIT OPERATION LOW BEAM LAMP(S) DO NOT OPERATE TEST HEADLAMPS Voltage is applied to the Light Switch at all times. The Light Switch includes a Self-Resetting Circuit Breaker. The Circuit Breaker opens when the Headlamp circuit draws too much current. When the Circuit Breaker opens, it interrupts the current flow. With no current flow the Circuit Breaker cools off and resets automatically. When the Light Switch is in HEAD, the Dimmer Switch directs voltage to either the Low Beams or the High Beams. The High Beam Indicator also receives voltage along with the High Beams. When the Light Switch is in PARK or HEAD, voltage is directed to parklamps. CANADIAN DAYTIME RUNNING LAMPS Voltage is applied to the Daytime Running Lamp (DRL) relay at all times through the ORN (240) wire from the DRL Fuse and when the Ignition Switch is in RUN through the PNK/BLK (39) wire from the GAGE/IDLE Fuse. The DRL Relay provides voltage to the LH High Beam through the DK BLU/ORN (593) wire. This wire also becomes the ground wire when the Headlamps are operated normally. Voltage is applied to the DRL Module when the Ignition Switch is in RUN through the PNK/BLK (39) wire from the GAGE/IDLE Fuse. When the Ignition Switch is placed in RUN the DRL Module energizes the DRL Relay connecting the ORN (240) circuit (hot at all times) with the DK BLU/ORN (593) circuit, turning on the Headlamps. Test lamp does not light. GO to step 5. Test lamp lights. GO to step 2. 2. Test lamp does not light. LOCATE and REPAIR open in BLK (150 or 151) wire(s) from headlamp connector(s) C138 or C144 (Base), C149 or C154 (Quad Halogen) to ground terminal(s) G105, G106 or G107. (For Canadian vehicles w/o Quad Halogen, GO to step 3.) Test lamp lights. REPLACE headlamp(s). Connect a test lamp from BLK (150) wire at DRL relay connector C126 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from DRL relay to ground G105. Connect a self powered test lamp from DK BLU/ORN (593) at DRL relay connector C126 to ground. Test lamp lights. LOCATE and REPAIR open in DK BLU/ORN (593) wire from headlamp connector C138 to DRL relay C126. Test lamp does not light. REPLACE DRL relay. Test lamp does not light. GO to step 6. Test lamp lights. LOCATE and REPAIR open in TAN (12 ) wire from headlamp dimmer switch to headlamp. Test lamp does not light. LOCATE and REPAIR open in YEL ( 10) wire from headlamp dimmer switch to light switch. Test lamp lights. REPLACE headlamp dimmer switch. 3. 4. DIAGNOSIS - HEADLAMPS PRELIMINARY CHECKS: Check condition of T/L CTSY fuse. If fuse is blown, LOCATE and REPAIR source of overload, then REPLACE 5. TEST 1. Connect a test lamp from RED (2) wire at light switch connector C202 to ground. 2. With the light switch on and the headlamp dimmer switch to HIGH BEAM, connect a test lamp from YEL (10) wire at light switch connector C202 to ground. 3. Connect a test lamp from LT GRN (1 1 ) wire at headlamp dimmer switch connector C201 to ground. Connect test lamp from TAN (12) to BLK (150 or 151) wire(s) at headlamp connectors C138 or C144 (Base), C149 or C154 (Quad Halogen) to ground. (For Canadian vehicle w/o quad, DK BLU/ORN (593) is used in place of BLK (150) wire at connector C138). fuse. If fuse is in good condition, use the following diagnostic procedures. HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS—BOTH SIDES RESULT Connect a test lamp from TAN (12 ) wire at headlamp dimmer switch connector C201 to ground. ACTION Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from light switch to junction block. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Test lamp lights. REPAIR open in LT GRN (11) wire from headlamp dimmer switch to headlamps. Test lamp does not light. REPLACE headlamp dimmer switch. ACTION 1. Turn light switch ON and headlamp dimmer switch to LOW BEAM position. Connect a test lamp from TAN (12) wire at inoperative lamp(s) to ground. When the Headlamps are turned on manually, or the Ignition Switch is turned OFF, the DRL Module de­ energizes the DRL Relay connecting the DK BLU/ORN (593) circuit to the BLK (150) ground circuit. This allows normal operation of the Headlamps. If the dimmer switch is put into the High Beam Position, the DRL Module will supply voltage through the WHT (629) wire, to the Instrument Panel Cluster to turn on the High Beam Indicator bulb. RESULT 6. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C201 to ground. HEADLAMPS A-23 HIGH BEAM LAMP(S) DO NOT OPERATE 1. 2. 3. 4. 5. Test lamp does not light. GO to step 5. Test lamp lights. GO to step 2. Connect test lamp from LT GRN (11) wire to BLK (150 or 151) wire(s) at headlamp connectors C138 or C144 (Base), C150 or C155 (Quad Halogen). (For Canadian vehicles, DK BLU/ORN (593) wire is used in place of BLK (150) wire at connector C138 or C155). Test lamp does not light. Test lamp lights. REPLACE headlamp(s). Connect a test lamp from BLK (150) wire at DRL relay connector C126 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from DRL relay connector to ground G105. Connect a self powered test lamp from DK BLU/ORN (593) wire to ground to DRL relay connector C126 to ground. Test lamp lights. LOCATE and REPAIR open in DK BLU/ORN (593) wire at headlamp connector C138 or C150 to DRL relay C126. 6. Connect a test lamp from YEL (10) 2. LOCATE and REPAIR open in BLK (150 or 151) wire(s) at headlamp connector(s) C138 or C144 (Base), C150 or C155 (Quad Halogen) to ground connection(s) G105, G106 or G107. (For Canadian vehicles: GO to step 3). Test lamp does not light. REPLACE DRL relay. Test lamp does not light. GO to step 6. Test lamp lights. LOCATE and REPAIR open in LT GRN (11) wire from headlamps to headlamp dimmer switch. Test iamp does not light. LOCATE and REPAIR open in YEL ( 10) wire headlamp dimmer switch to light switch. Test lamp lights. REPLACE headlamp dimmer switch. wire at headlamp dimmer switch connector C201 to ground. PRELIMINARY CHECKS: Lamp(s) are inoperative, refer to the HIGH BEAM LAMP(S) DO NOT OPERATE test procedures. If the High Beam Lamp(s) are operative, use the following diagnostic procedures, after placing the Light Switch to OFF position. Before checking the DAYTIME RUNNING LAMPS system, do the following: 1. Place Park Brake in the OFF position. 2. Place Light Switch to ON and Headlamp Dimmer Switch to HIGH BEAM position. If the High Beam 5. Fuse is blown. LOCATE and REPAIR source of overload. Then, REPLACE fuse. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire from DRL relay connector C126 to C125 and/or ORN (340) wire between C125 to fuse block. Fuse is not blown. GO to step 4. Fuse is blown. LOCATE and REPAIR source of overload. Then, REPLACE fuse. Place ignition switch to run. Connect a test lamp from PNK/BLK (39) wire at DRL relay connector C126 to ground. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in PNK/BLK (39) wire between DRL relay and fuse block. Connect a test lamp from PNK/BLK (39) wire at DRL module connector C221 to ground. Test lamp lights. GO to step 6. Test lamp does not light. LOCATE and REPAIR open in PNK/BLK (39) wire between DRL module and fuse block. Daytime Running lamps light. GO to step 7. Daytime Running Lamps do not light. GO to step 9. Test lamp lights. GO to step 8. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire between DRL module connector C 2 1 1 and ground G 200. Test lamp lights. REPLACE DRL relay. Test lamp does not light. LOCATE and REPAIR open in LT GRN/BLK (592) wire between DRL relay connector C126 and DRL module connector C211. Test lamp lights. LOCATE and REPAIR open in DK BLU/ORN (593) wire between DRL relay connector C126 and LH headlamp connector C138 or C150. Test lamp does not light. REPLACE DRL module. Connect a test lamp from ORN (240) wire at DRL relay connector C126 to ground. 6. Using a jumper wire, apply ground to LT GRN/BLK (592) wire at DRL module connector C211. 7. Connect a self-powered test lamp from LT GRN/BLK (592) wire to BLK (150) wire at DRL module connector C211. 8. Connect a self-powered test lamp from LT GRN/BLK (592) wire at DRL relay connector C 126 to ground. 9. Connect a test lamp from DK BLU/ORN (593) wire at DRL relay connector C126 to ground. DRL STAY ON RESULT TEST 1. Disconnect DRL module connector C211. Place ignition switch to RUN and light switch to ON position. Connect a J 34209-A multimeter (or equivalent) to YEL (10) wire from module connector to ground. Measure voltage. A-24 HEADLAMPS ACTION Battery voltage. REPLACE DRL module. No voltage. LOCATE and REPAIR open in YEL (10) wire from DRL module to light switch. ACTION GO to step 2. 3. Check condition of GAGE/IDLE fuse. 4. RESULT Fuse is not blown. 1. Check condition of DRL fuse. Place light switch to ON and dimmer switch to HIGH BEAM position. Connect a test lamp from LT GRN (11) wire at inoperative lamp(s) to ground. Connect a test lamp from LT GRN ( 1 1 ) wire at headlamp dimmer switch connector C201 to ground. TEST ACTION RESULT TEST DRL DOES NOT OPERATE RPO CODES (SEE POWER DISTRIBUTION) C60 - FRONT MANUAL AIR CONDITIONING L05 - 5.7L (350 CU. IN.) V8 GAS ENGINE VIN K L19 - 7.4L (454 CU. IN.) V8 GAS ENGINE VIN N LH6 - 6.2L (378 CU. IN.) V8 DIESEL ENGINE VIN C LL4 - 6.2L (378 CU. IN.) HD V8 DIESEL ENGINE VIN J M20 - MANUAL 4-SPEED TRANSMISSION pJ=U . r^inr^i (SEE POWER DISTRIBUTION) □ BATTERY JUNCTION BLOCK 0 QDUCZJ B nB S nS tz fe □n O QDu „ClI C203 12066261 l/P CLUSTER CONNECTOR (SEE PAGE 103) m um J Z r ■ ■2-1.0 R S T B H (FUSIBLE LINK) I 2-3.0 RED I 12-1.0 RST I (FUSIBLE LINK) 5100 (LH6, LL4) 5101 (L05, L19) 420 440 439 806 AUXILIARY ENGINE COOLING FAN (L19 AND C60) L ■151-2.0 BLK ■ (SEE PAGE 90) PARK AND TURN LAMPS (SEE PAGE 34) ■151-.8 B L K i : 18 120 : 24 30 I • 19 I C100 12020184 140 2 39 120 31 3 D ] r 50 436 35 2 93 97 422 91 92 6 : l/P ■11-1.0 L T G R N l | 12-.8 TAN lA L GENERATOR (SEE PAGE 10) 151-.8 BLK 151-3.0 BLK HEAD . OFF 40- C138 12034372 C144 12034372 ''P A R K HEAD RH HIGH-LOW HEADLAMP SHEET METAL GROUND G106 FRAME GROUND G107 LH HIGH-LOW HEADLAMP SHEET METAL GROUND G105 LIGHT SWITCH HEADLAMPS A-25 BASE HOT IN START OR RUN GAGE/ IDLE 20 AMP V22 t~ ...-J ni 2 r ii ^ a LH HIGH-LOW HEADLAMP | 440 I 420 HI r a s m [ 1 2 0 | 140 | | [ ] | i 3 h y * n | ! 31 | 436 | 50 | ^ i p ( " 2 1 35 i l m I , | 422 | 97 | 93 | A-26 HEADLAMPS W/DRL 5.7L, 7.4L V 8 GASOLINE ENGINE, 6.2L HEAVY DUTY DIESEL W/MAN TRANS FLEETSIDE, WIDESIDE, CREW-BONUS CAB SHEET METAL GROUND G105 SHEET METAL GROUND G106 FRAME GROUND G107 . | 6 1 | 92 | 91 2 3 | C3 C100 12020183 c = i RPO CODES P t s m _ O Z * i ifl h = ==o5m=32'^: P; Qi d ° :5Z nO < < ^ S 2 o m c l S x x A l I I w j clq ^ o I DIODE ASSEMBLY DRL MODULE C291 12040549 (UTILITY ONLY) (FLEETSIDE, WIDESIDE CREW/BONUS CAB) PARK BRAKE WARNING SWITCH RWAL (UTILITY ONLY) (SEE PAGE 116) o c c o o I 060 - AIR CONDITIONING L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN E L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N LL4 - ENGINE, 6.2L (378 CID) V8, HD DIESEL ENGINE, VIN J V22 - QUAD HALOGEN HEADLAMPS DIODE ASSEMBLY (CLOSED WITH PARK BRAKE APPLIED) inn * T. 592-.8 LT GRN/BLK I _ J C293 12004267 33-.5 TAN/WHT sc m 5 I I i 33-.5 TAN/WHT & ■onifpEi G»]nljD ■ r j t a 592-.a l t g r n / b lk M r - jm m r jm m r j h (SEE PAGE) 131 lir a 4 OH[][II] t n _ ——.=»»«'-------------------------—"L _ L I_iHoili ____ _____ I 39*.8 PNK/BLK | _____________________ U * 33-.5 TAN/WHT . (SEE PAGE 116) 12-.8 TAN - 39-.S PNK/BLK I I \ w J \ PNK/BLK I ■ ■ H ■ ■ H ■ ■ V ......... ..... - - - ......r ^ \ ^ a r (SEE (SEE PAGE PAGE 105) 105) LOW COOLANT WARNING MODULE i (SEE PAGE 104) 39-. 5 p n k /b lk m w ,= ^ M r m um r J I z 2 £ . I I (L| 4 0 N | Y) J « a r r = j •IS n O D □ dt=M UdI d ^ X » r V-’ | P 7 I 1 1-------------------------------^ U 12066261 I I I -.m I * I --------- 39-.S PNK/BLK (LL4 ONLY) r- S201 110-1.0 YEL I I 150- (SEE PAGES 17, 19) LIGHT SWITCH I 150-.8 BLK I 156 I 12-.8 TAN 2— CIRCUIT BREAKER 25 AMP IGNITION SWITCH I I 11-1.0 LT GRN I I 39-.S PNK/BLK 1 ^ ^ I WATER IN FUEL LAMP . ^ 1 3 9 -1 1 _ CONVENIENCE CENTER (SEE PAGE 21) FUEL PUMP CYCLE RELAY (SEE PAGE 78) S202 i i I 11-1.0 LT GRN m m 1 jm l/P CLUSTER CONNECTOR (UTILITY ONLY) z f RWAL __________ I 33-. 5 TAN/WHT 33-.5 TAN/WHT i m I 11-.8 LT GRN 33-.5 TAN/WHT 33-.5 TAN/WHT DIMMER SWITCH G2O0 l/P ' GROUND 10-1.0 YEL HEADLAMPS A-27 W/DRL 5.7L, 7.4L V8 GASOLINE ENGINE, 6.2L HEAVY DUTY DIESEL W/MAN TRANS FLEETSIDE, WIDESIDE, CREW-BONUS CAB_____________________________________ W/LL4 / ■ 50-2.0 BRN I vMWMAMM < HOT AT ALL TIMES < m w w vw s HTR/AC 25 AMP DRL 15 AMP \ GAGE/IDLE 20 AMP 592-.8 LT GRN/BLK . I PNK/BLK L ______ J RH HIGH-LOW HEADLAMP DRL RELAY GT105 12020457 —jLoxmju— 592-.8 LT GRN/BLK . I 340-,8 ORN I 12052641 592-.S LT GRN/BLK RH LOW BEAM HEADLAMP RH HIGH BEAM HEADLAMP 11-.8 LT GRN I V22 ONLY 11-1.0 LT GRN 11 39-.5 PNK/BLK LH HIGH BEAM HEADLAMP J r 1 1 t 39 14 29 15 12-.8 TAN ■ C102 12020100 39-.8 PNK/BLK I GENERATOR ^ (SEE PAGE 12) LH LOW BEAM HEADLAMP I 151-3.0 BLK LH HIGH-LOW HEADLAMP L _ 593- 8 DK BLU/ORN^ ___________________________ i A-28 HEADLAMPS W/DRL 5.7L DIESEL ENGINES AND 4-SPD., AUTO TRANS SUBURBAN/UTILITY (Q ) (q ) SHEET METAL GROUND G105 SHEET METAL GROUND G106 FRAME GROUND G107 RPO CODES ___ W/LL4 S203 I 50-2.0 BRN I DRAC (SEE PAGE 75) ■ a n 50-1.0 BRN ■ ■ TTl m I 5 £ _3 I “ £ 2 5 i £ <£fl I- kO 5 g h tc aa:*S(/>i-00 ; 0 5 « 3 3 i uZ 03 l 2 111 3 DIODE ASSEMBLY DIODE ASSEMBLY L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K LL4 - ENGINE, 6.2L (378 CID) V8, HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (370 CID) V8 DIESEL ENGINE, VIN C MD8 - AUTO TRANS, 4 SPD.pWITH OVERDRIVE V22 - QUAD HALOGEN HEADLAMPS MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE (EXCEPT LL4) (W/LL4) DRL MODULE RWAL O (SEE PAGE 116) f^ r Ps rQ f i Wo - °i ZI go HTR SW (SEE PAGE 9 6 )' PARK BRAKE WARNING SWITCH RWAL (SEE PAGE 116) {CLOSED WITH PARK BRAKE APPLIED) ^ o 592-.8 LT GRN/BLK 33-. 5 TAN/WHT I I W/MD8 C293 12004267 % I _____________ 39 -.8 p n k /b lk r mmmr m Mmm 33 -. 5 t a n / w h t w a rn k.^1 jm m w ja m m ^ 33 -. 5 TAN/WHT ta n /w h t I 33-. jm m w 33-. 5 TAN/WHT I 33-.5 TAN/WHT I 133-.8 TAN/WHT 33-. 8 TAN/WHT ~ l .___ , fcJ 629-.8 w h t mm l/P CLUSTER I CONNECTOR (SEE PAGE 103) G»]n[jD 150-.8 BLK | 31 I U [ 4 1 9 | HGilnljD 111-,8 IT GRN 5Q DnS 6 LH J 592 | U | 2 3 t [ U n ra r ~ - 'r a t e dDuQD 39-.S PNK/BLK WATER IN FUEL I 11-1.0 LT GRN I V J V 39' 8 PNK/BLK 1 \ I 39-,8 PNK/BLK L ............... __ J A M P t ^ % 39-.5 PNK/BLK b t I 12-,8 TAN I ™ j v j w (SEE PAGE 105) (LH6 ONLY) ^ ^ N T WARNING MODULE (SEE PAGE 104) jm m r J J I I I I ^ 1 = J H T ^ 1 | I m am l 12,8 TAN 1 11-1.0 LT GRN I ^ I r I I I 150-1.0 BLK ■ S201 (SEE PAGES 17, 19) 110-1.0 YEL I 150-.8 BLK I LIGHT SWITCH 1 1 C203 12066261 150- I 12-. 8 TAN 2— DIMMER SWITCH CIRCUIT BREAKER 25 AMP IGNITION SWITCH 10-1.0 YEL G200 l/P GROUND HEADLAMPS A-29 W/DRL 5.7L DIESEL ENGINE AND 4-SPD., AUTO TRANS SUBURBAN/UTILITY HOT IN RUN ' HTR A/C 25 AMP a | ! RH LOW BEAM HEADLAMP RH HIGH BEAM HEADLAMP V22 ONLY LH HIGH BEAM HEADLAMP LH LOW BEAM HEADLAMP LH HIGH-LOW HEADLAMP A-30 HEADLAMPS W/DRL 5.7L, 7.4L GASOLINE ENGINE, 6.2L HEAVY DUTY DIESEL ENGINE W/HEAVY DUTY AUTO TRANS, SUBURBAN, FLEETSIDE, WIDESIDE, CREW-BONUS CAB SHEET METAL GROUND G105 SHEET METAL GROUND G106 C 100 12020183 FRAME GROUND G107 39*. 8 PNK/BLK I S202>k Ovv I 11-1.0 LT GRN I 39-.8 PNK/BLK ■ | — m 3 9 - 8 p n k /b lk ■ m m m m b ^ r 1 m k ■ ■ ■ » l o w c o o l a n t w a r n in g m o d u le (SEE PAGE 104) (LL4 ONLY) I I I I 39- 5 p n k /b lk v I ^ I 1 2,8 TAN I I % ■ ■ ■ ■ ■ ■ k I 0203 12066261 v' ^ m r I 11-1.0 LT GRN I S201 (SEE PAGES 17, 19) I 10-1.0 YEL I 44 (L05/L19 W/O RWAL BRAKES) LIGHT SWITCH L _ y _ _ 150- X I 12-. 8 TAN DOME 2 - IL/ OFF CIRCUIT BREAKER 25 AMP i '•P A R K ¥ HI 1 I 11 r l*°jf 12^ 10 i *- HEAD OFF IGNITION SWITCH DIMMER SWITCH T\ 'P A R K HEAD t G200 l/P ^ GROUND 10-1.0 YEL HEADLAMPS A-31 W/DRL 5.7L, 7.4L GASOLINE ENGINE, 6.2L HEAVY DUTY DIESEL ENGINE W/HEAVY DUTY AUTO TRANS, SUBURBAN, FLEETSIDE, WIDESIDE, CREW- BONUSCAB RPO CODES (SEE POWER DISTRIBUTION) C60 - AIR CONDITIONING L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, V1N K L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL-ENGfNE, VIN C LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J M20 - MAN TRANS, 4-SPD. BATTERY DIMMER SWITCH GROUND G105 A-32 QUAD HALOGEN HEADLAMPS GROUND G106 LIGHT SWITCH ROOF MARKER LAMPS DO NOT OPERATE CIRCUIT OPERATION TEST HAZARD LAMPS Voltage is applied at all times, through the STOP/HAZ Fuse and the Hazard Flasher to the normally open contact of the Hazard Switch in the Turn Signal Switch Assembly. With the Hazard Switch in HAZARD FLASH, voltage is applied to both Front and Rear Turn Lamps. All of the Turn Lamps and both Turn Indicators flash on and off. The Front Marker Lamps flash in HAZARD FLASH just as they do in RIGHT TURN and LEFT TURN. If the Lamp Switch is in OFF, they flash on when the Hazard Lamps are on. If the Light Switch is in either PARK or HEAD, they flash on when the Hazard Lamps are off and off when the Hazard Lamps are on. 1. RESULT Connect test lamp from ORN (40) wire at light switch connector C202 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire between light switch and fuse block or REPLACE (T/L CTSY) fuse. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in WHT (45) and BRN (9) wires from marker lamp to light switch. Test lamp lights. CHECK condition of light socket. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from marker lamps to bus bar ground. In Hazard, this circuit is always open, and the Hazard Flasher control the Lamps. PARK AND MARKER LAMPS Voltage is applied through the T/L CTSY Fuse to the Light Switch at all times. With the Light Switch in PARK or HEAD, voltage is applied to the Park, Tail, Marker, License Lamp and Roof Marker Lamps (if so equipped). 2. 3. 4. DIAGNOSIS - FRONT PARK, MARKER ROOF AND HAZARD LAMPS Connect test lamp from BRN (9) wire at light switch connector C202 to ground. Connect test lamp at WHT (45) wire at LH marker lamp terminal to ground. Connect test lamp from WHT (45) wire to BLK (150) wire at LH marker lamp. ACTION FRONT PARK AND SIDE MARKER LAMPS DO NOT OPERATE TEST 1. 2. 3. Place light switch in PARK position. Connect a test lamp from ORN (40) wire at light switch connector C202 to ground. Connect test lamp from BRN (9) wire at light switch connector C202 to ground. Connect a test lamp at BRN (9) wire at LH park lamp connector C140 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire between light switch and fuse block or REPLACE T/L CTSY fuse. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Test lamp lights. CHECK conditions of bulb sockets and BLK (150 and 151) wires from park lamps to ground terminals G106 and G107. Test lamp does not light. HAZARD WARNING LAMPS DO NOT OPERATE ACTION RESULT LOCATE and REPAIR open in BRN (9) wire from park lamps to light switch. TEST 1. Place ignition switch in RUN and position turn signal lamps as if making a turn. RESULT ACTION Turn signal lights operate. GO to step 2. Turn signal lights do not operate. GO to step 3. 2. Turn off turn signal lamps and put hazard warning lamps on. Connect a test lamp from BRN (27) wire at turn signal switch connector C205 to ground. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. CHECK condition of fuse (STOP/HAZ) and an open in ORN (140) wire and BRN (27) wire. If fuse and wiring are good, REPLACE hazard flasher. 3. Place hazard lamps on. Connect test lamp from LT BLU (14) wire at turn signal switch connector C205 to ground. Test lamp flashes. LOCATE and REPAJR open in wires from turn signal switch to convenience center. Test lamp does not light. REPLACE turn signal switch. FRONT, PARK AND MARKER LAMPS A-33 RPO CODES wvwwwww/ > RADIO/CLOCK (SEE PAGES 144, 145) 40-.8 O B N I HOT A T ALL TIM ES < ^wwwwwv^T C60 - AIR CONDITIONING L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N T61 - CANADIAN DAYTIME RUNNING LAMPS T/L CTSY 20 AMP AUXILIARY ENGINE COOLING FAN (L19 WITH C60) (SEE PAGE 90) RH PARK AND TURN LAMP ♦ 1S6 I ■151-2.0 B LKl RH HIGH-LOW HEADLAMP (SEE PAGE 25) 151-.8 BLK ■ LIGHT SWITCH RH PARK AND TURN LAMP RADIO/CLOCK (SEE PAGES 144, 145) 115-. 8 DK BLU I I1 4 -.8 L T B L U I LH PARK AND TURN LAMP \ I X r i LH HIGH-LOW HEADLAMP (SEE PAGE 25) — - i ~7) t i^ J "s' m z ^ m 8g £ eq O 94 9 29 39 33 12 : 93 11 15 14 420 J 1 (© ] r 93 co 91 i 1 1 50-.8 B LK l C100 1202184 D m b CO LH PARK AND TURN LAMP C137 12077765 LH SIDE MARKER LAMP A-34 FRONT, PARK AND MARKER LAMPS BASE SHEET METAL GROUND G105 SHEET METAL GROUND G106 J FRAME GROUND G107 440 806 2 39 140 120 31 3 SO 436 35 2 97 422 92 6 : TURN LAMPS SWITCH (SEE PAGE 45) RPO CODES < HOT AT ALL TIMES < HOT AT ALL TIMES < >V V W V W V V W N STOP HAZ 15 AMP RH PARK AND TURN LAMP RH PARK AND TURN LAMP LH PARK AND TURN LAMP LH PARK AND TURN LAMP A-36 HAZARD LAMPS BASE HAZARD LAMPS A-37 _________________ BASE________ vjViMWWVvV* S 140-.8 0RN HOT AT ALL TIMES < “Vw m w v w n 140-.8 0RN (L0S/L19 WITH M20 FLEETSIDE, WIDESIDE, CREW/BONUS CAB) STOP HAZ 15 AMP RH PARK AND TURN LAMP C153 12077753 A-38 HAZARD LAMPS W/QUAD HALOGEN HEADLAMPS SHEET METAL GROUND G105 SHEET METAL GROUND G106 FRAME GROUND G107 vAAWMAAAM < T/LCTSY 20 AMP *) Ui HOT AT ALL TIMES < > W W V W V \W S CTSY LAMPS I 40-.8 ORN | I 40-.8 ORN I S204 (SEEPAGE 119) 40-.8 ORN | RH MARKER LAMP / ( «5 ) FRONT IDENTIFICATION / LAMPS M m g G *D \ LH MARKER LAMP r r t u f I 45-. 8 W H TI A-40 ROOF MARKER LAMPS RADIO/CLOCK (SEE PAGES 144, 145) BLANK BLANK A-41 DIAGNOSIS — TURN SIGNAL LAMPS CIRCUIT OPERATION PRELIMINARY CHECKS: TURN SIGNAL LAMPS With the Ignition Switch in RUN or START, voltage is applied through the TURN/BU Fuse and Turn Signal Flasher to the normally closed contact of the Hazard Flasher Switch in the Turn Signal Switch Assembly. ground. The Marker Lamp will flash with the Turn Lamps. The Lamps used for the ground path will not flash, however, since the voltage drop across the Marker Lamp is much higher than that across the other Lamps. With the Turn Signal Switch in LH Turn position, voltage is applied to both the LH Turn Indicator and the LH Front Park/Turn Lamp (LT BLU wires). Voltage is applied to the LH Rear Turn Lamp (YEL wire). When the Light Switch is in either PARK or HEAD, voltage is applied through the T/L CTSY Fuse, Lamp Switch and splice S112 to the Marker and Park Lamps. If the Turn Signal Switch is in LEFT TURN, the LH Front Marker Lamp will have voltage at both connections and will go out. When the flasher removes voltage to the Turn Lamp, the Marker Lamp will be grounded through the Turn Lamp and will go on. In this way, the LH Front Marker Lamp will flash on when the LH Front Park and Turn Lamp goes off, and off when the Turn Lamp goes on. The Lamps go on immediately. They begin to flash when the current flow heats up the timing element in the flasher and it repeatedly opens and closes the circuit. The voltage applied to the LH Front Park and Turn Lamp will also be applied to the LH Front Marker Lamp. If the Light Switch is in the OFF position, the LH Front Marker Lamp will find a path to ground through splice S112 and the many Lamps connected in parallel to ground. These Lamps provide low resistance paths to With the Turn Signal Switch Assembly in RIGHT TURN, voltage will be applied to the RH Lamps in a similar manner. 1. Check condition of TURN/BU fuse. If fuse is blown, LOCATE and REPAIR source of overload, then REPLACE fuse. 2. Place Headlamp Switch in PARK position. If any park or marker lamps do not operate, refer to FRONT TURN SIGNALS DO NOT WORK ON ONE SIDE TEST 1. Turn hazard warning system ON. Observe lights on side of turn signals that did not work. RESULT ACTION Lights flash. CHECK for improper bulb. REPLACE if necessary. Lights do not come on. GO to step 2. 2. Turn hazard warning system off. Place ignition switch to RUN and turn signal to side that does not work. Connect test lamp from LT BLU (14) or DK BLU (15) wire (depending on which side does not work) at turn signal switch connector C205 to ground. Test lamp lights. GO to step 4. lamp does not light. GO to step 3. 3. Connect a test lamp from PPL (16) at turn signal switch connector C205 to ground. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. REPLACE turn signal flasher. Connect a test lamp from LT BLU (14) or DK BLU (15) wire (depending on which side did not work) at park and turn lamp connector C137, C140, C145, C146, C147 (Base) or C151, C152, C153, C156, C157, C158 (Quad Halogen) to ground. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in either LT BLU (14) or DK BLU (15) wires. Connect a test lamp from LT BLU (14) or DK BLU (15) wire to BLK (150 or 151) wire at park and turn lamp connector C139, C140, C146, C147 (Base) or C151, C156 (Quad Halogen). Test lamp lights. CHECK condition of bulb sockets. Test lamp does not light. LOCATE and REPAIR open in BLK (150 or 151) wire. 4. 5. A-42 TURN SIGNAL LAMPS PARK AND SIDE MARKER LAMPS DO NOT OPERATE diagnostic procedure in this manual. If the park or marker lamps are operative, use the following diagnostic procedure. TURN SIGNALS DO NOT OPERATE RESULT TEST 1. 2. 3. ACTION Hazard lamps operate. GO to step 2. Hazard lamps do not operate. GO to step 3. Connect a test lamp from PPL (16) wire are turn signal switch connector C205 to ground. Test lamp flashes. REPLACE turn signal switch. Test lamp does not light. CHECK condition of fuse (TURN/BU) and an open in PPL (16) wire, DK BLU (38) wire, or BLK (150) wire. If fuse and wiring are good, REPLACE turn signal flasher. Place ignition switch in RUN position and put turn signal switch as if making a LH turn. Connect a test lamp from LT BLU (14) wire at turn signal switch connector C205 to ground. Test lamp flashes. LOCATE and REPAIR open in wires from turn signal switch to convenience center. Test lamp does not light. REPLACE turn signal switch. Place hazard warning lamps to ON position. TU R N S IG N A L LAM PS FLASH RAPIDLY TEST Turn hazard lamp switch ON. Check front signal lamps and rear taillamps. RESULT ACTION One side of turn signal lamps flash rapidly. REPLACE inoperative turn signal bulb. Only one side of turn signals light but do not flash rapidly. REFER to “Turn Signals Do Not Operate On One Side" symptom. TURN SIGNAL LAMPS A-43 I 16-.8 PPL I i/P CLUSTER CONNECTOR (SEE PAGE 103) C203 12026261 D u n a |lSO|U|~39~] Q iln E H l U D T3 rn n U r^ B n C ID p E 3 n l3 D QDUE3 p 14-.8 LT BLU I 94 29 15 14 N 9 39 M 33 12 L 93 11 II (i RH SIDE MARKER LAMP I 15-. 8 D K B LU I 420 440 439 806 / 39 y I 140 120 I1 4 -.8 L T B IU I 31 50 436 r 93 35 2 97 422 91 92 6 RH PARK AND TURN LAMP 19-.8D KG R N I 18-.8YEL^H RH PARK AND TURN LAMP 15-.8 DK BLUi 151-.8 BLK RH HIGH/LOW HEADLAMP (SEE PAGE 25) AUXILIARY ENGINE COOLING FAN (L19 WITH C60) (SEE PAGE 90) ■■■■ M 151-2.0 B L K M LH PARK AND TURN LAMP LH PARK AND TURN LAMP |A-44 LH SIDE MARKER LAMP t u r n s ig n a l l a m p s base SHEET METAL GROUND G105 SHEET METAL GROUND G106 FRAME GROUND G107 RPO CODES E63 ■ FLEETSIDE BODY R05 - DUAL REAR WHEELS T61 - CANADIAN DAYTIME RUNNING LAMPS L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N C60 • AIR CONDITIONING 17 16 27 - 17-.8 WHT 19-.8 DK GRN - 18-.8 YEL 16-.8 PPL 27-.S BRN - 15-.5 DK BLU 14-.5 LT BLU 28-.5 BLK - 80-. 5 LT GRN - 159-.8 TAN a SHEET METAL GROUND G403 SHEET METAL GROUND G402 (SURBURBAN/UTIUTY ONLY) C412 8911035 (SUBURBAN) (SURBURBAN ONLY) TURN SIGNAL LAMPS A-45 _______________________ BASE________ HTR II © a ^BAT-1 B m ! 16-.8 PPL I m id hi id i 1 1 1 I! FUSE BLOCK m @ E 12103404 ^ WDO ID [c] B 0 MGNJ SHUNT i ACC LPS PWR y LPL 1 111111A111111 ° t i [ ] A in i ] ei i i SHUNT .NSTR [I m \ __ Jhi 15-.8 DK BLU n m K L D I lL d O UE LsJ T/L CTSY LH PARK AND TURN LAMP 15-.8 DK BLU K l ECM B KECM l1 KDRL] c d B 'f l'x AUXILIARY ENGINE COOLING FAN (L19 WITH C60) (SEE PAGE 90) o cCRANK *a □ □ RH PARK LAMP (SEE PAGE 40) FRONT 151-.8 BLK RH LOW BEAM HEADLAMP (SEE PAGES 25, 32) ' S111 ■ 1 151-2.0 BLK J\ RH HIGH BEAM HEADLAMP ] (SEE PAGES 25, 32) TURN SIGNAL FLASHER Ai LH HIGH BEAM HEADLAMP (SEE PAGES 25, 32) LH LOW BEAM HEADLAMP (SEE PAGES 25, 32) 1150-.8 BLK LH PARK LAMP (SEE PAGE 40) I150-.8 BLK 150-.8 BLK I 150-.8 BLK RH PARK AND TURN LAMP 14-.8 LTGRN I 151-.8 BLK I 14-.8 LTGRN I SHEET METAL GROUND G105 A-46 TURN SIGNAL LAMPS W/QUAD HALOGEN HEADLAMPS a fl SHEET METAL GROUND G106 FRAME GROUND G107 15-.8 DK BLU RPO CODES CIGARETTE LIGHTER DOES NOT OPERATE CIRCUIT OPERATION TEST When the Horn Switch is depressed, one side of the cojl of the Horn Relay is grounded. The relay is energized. The relay contacts close and battery voltage is applied to the horns. DIAGNOSIS - HORNS PRELIMINARY CHECKS: Check condition of HORN/DM fuse. If fuse is blown, LOCATE and REPAIR source of overload, then REPLACE fuse. If fuse is in good condition, use the following diagnostic procedure. HORN(S) WILL NOT OPERATE TEST RESULT ACTION 1. Connect a test lamp from BLK/LT GRN (29) wire at horn connector (C142, C143) to ground. Press horn switch. Test lamp lights. REPLACE horn. Test lamp does not light. GO to step 3. 2. Remove horn relay. Connect a test lamp from ORN (240) wire at convenience center to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire between convenience center and fuse block. Disconnect turn signal switch connector C205. Use a jumper wire to ground BLK (28) wire at turn signal switch connector C205. Horn does not sound. GO to step 4. Horn sounds. REPLACE turn signal switch. Disconnect horn relay. Install a jumper wire from ORN (240) terminal to DK GRN (29) terminal at convenience center. Horn sounds. REPLACE horn relay. Horn does not sound. LOCATE and REPAIR open in DK GRN (29) wire from convenience center to C100 and/or LT GRN/BLK (29) wire between C100 and horn(s). 3. 4. HORN SOUNDS CONTINUOUSLY WITHOUT DEPRESSING HORN SWITCH RESULT TEST 1. 2. Disconnect turn signal switch connector C205. Disconnect horn relay. Check for a short to ground in DK GRN (29) and BLK (29) wires. A-48 HORNS ACTION Horn stops. REPLACE turn signal switch. Horn continues to sound. GO to step 2. No shorts found. REPLACE relay. Short(s) found. REPAIR or REPLACE as required. 1. Connect a test lamp at cigarette lighter connector C299 from ORN (240) wire to ground. RESULT ACTION Test lamp lights. REPLACE cigarette lighter. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire between fuse block and cigarette lighter connector C299. v/AAAW W W W S HOT AT ALL TIMES < m A /w W W V S HORN/DM 20 AMP J) C CONVENIENCE CENTER 1240-1.0 ORN I RH HORN (STEERING C O L SW ITCHES) C143 y < -* z o 12004267 <75 — 17-.0 WHT 19-.8 DK GRN — 18-.8 YEL — 16-.8 PPL — 27-. 8 BRN - -C -J 15-.5 DK BLU- I *_ l I a: o 14-.5 LT BLU 2S-.5 BLK 80-.5 LT GRN 159-.8 TAN TURN SIGNAL SWITCH LH HORN C142 12004267 m z C102 12020100 HORNS A-49 WIPERS DO NOT OPERATE IN ANY MODE CIRCUIT OPERATION TEST 1. PULSE WIPERS PULSE In addition to MIST, LO and HI speed operation the pulse-type Wiper/Washer System includes an operating mode in which the wipers make single strokes with an adjustable time interval between strokes. The time interval is controlled by a Solid-State Pulse/Speed/Wash Control in the Wiper Motor Module. The duration of the relay interval is determined by the Pulse Delay Resistance in the Wiper/Washer Switch. With the Wiper/Washer Switch in PULSE (Delay), voltage is applied to the GRA (91) wire, the Wiper Motor Module, and the Solid-State Control Board. Voltage is applied to Park/Run Relay coil which is momentarily grounded by the Pulse/Speed/Wash Control circuit and the relay closes. Battery voltage is supplied through the closed contacts of the relay to the run Wiper Motor. The relay remains energized as long as the contacts of the Park/Run Switch remain closed. When the wiper blades have reached PARK, the Park/Run Switch opens, de­ energizing the Park/Run Relay. The wiper blades remain in PARK until the Control Board grounds the Park/Relay coil to start another sweep. The delay time between sweeps is controlled by the pulse delay resistors. The delay can be adjusted from 0 to 43 seconds. LOW SPEED In the LO position, the Wiper/Washer Switch supplies voltage in the GRA (91) wire and the Pulse/Speed/Wash Control. The Pulse/Speed/Wash Control provides ground to the Park/Run Relay which is energized and supplies voltage to the brushes of the Wiper Motor. The wipers run at low speed until they are turned off. 2. With the Wiper/Washer Switch in the HI position, battery voltage is supplied from the PPL (92) wire directly to a second armature terminal of the Wiper Motor. The wipers run at high speed. When the Wiper/Washer Switch is turned to OFF, the wipers complete the last sweep at low speed and park. PARK When the wipers are turned off, the Wiper Motor runs at low speed until the wiper blades reach the PARK position. At that time the Park/Run Relay opens and shuts the Wiper Motor to stop it immediately. The wiper blades remain in the PARK position. MIST When the control is moved to MIST and released, the wipers make one sweep at low speed and return to PARK. The circuit operation is the same as low speed. 2. The Wiper Motor is equipped with a circuit breaker which protects the motor when the wipers are blocked. The resulting high current will open the circuit breaker which will reset upon cooling. A-50 WINDSHIELD WIPERS AND WASHERS PULSE LOCATE and REPAIR open in WHT (93) wire between wiper motor connector C188 and fuse block. Test lamp lights. GO to step 2. Wiper motor runs. LOCATE and REPAIR open in BLK (150) wire between pulse wiper module connector C207 and ground G200. Wiper motor does not run. REPLACE wiper motor. Place ignition in RUN or ACC and wipers to HI. Connect a fused jumper from PPL (92) wire at pulse wiper module connector C207 to ground. Connect a fused jumper from PPL (92) wire at pulse wiper switch connector C204 to ground. ACTION Wiper motor does not run. LOCATE and REPAIR open in PPL (92) wire between wiper motor connector C188 and pulse wiper module connector C207. If no open is found, REPLACE wiper motor. Wiper motor runs. GO to step 2. Wiper motor does not run. LOCATE and REPAIR open in PPL (92) wire between pulse wiper switch connector C204 and pulse wiper module connector C207. If no open is found, REPLACE pulse wiper control module. Wiper motor runs. REPLACE wiper, washer switch. WIPERS DO NOT OPERATE IN LO OR DE LAY 1. 2. CHECK condition of WIPER fuse. If fuse is in good condition, use the following diagnostic procedure. Test lamp does not light. RESULT TEST DIAGNOSIS — WINDSHIELD WIPERS AND WASHERS (PULSE) PRELIMINARY CHECKS: Connect a fused jumper from BLK (150) wire at pulse wiper module connector C207 to ground. TEST 1. When the Washer Switch is depressed, voltage is applied to the Solid-State Control Board. The Control Board supplies a ground to the washer motor through the PNK (94) wire. It also starts the wiper cycle through the low speed brushes of the Wiper Motor. The washer continues to run as long as the switch is held down. The Solid-State Control Board keeps the wipers on for approximately six seconds after the washer goes off. If the washer is switched on during the PULSE operation, the wipers run in low speed for six seconds. The wash cycle is completed before the wipers return to the delayed pulse operation. Place ignition in RUN or ACC and turn wipers to HI. Connect a test lamp from WHT (93) wire at wiper motor connector C188 to ground. ACTION WIPERS DO NOT OPERATE IN HI WASHER HIGH SPEED RESULT Place ignition in RUN or ACC and wipers to LO. Connect a fused jumper from GRA (91) wire at pulse wiper module connector C207 to ground. Connect a fused jumper from GRA (91) wire at wiper switch connector C204 to ground. RESULT ACTION Wiper motor does not run. LOCATE and REPAIR open in GRA (91) wire between wiper motor connector C188 and pulse wiper module connector C207. If no open is found, REPLACE wiper motor. Wiper motor runs. GO to step 2. Wiper motor does not run. LOCATE and REPAIR open in GRA (91) wire between pulse wiper switch connector C204 and pulse wiper module connector C207. If no open is found, REPLACE pulse wiper control module. Wiper motor runs. REPLACE pulse wiper/washer switch. WASHER MOTOR DOES NOT OPERATE TEST 1. 2. 3. 4. 5. ACTION RESULT Test lamp does not light. LOCATE and REPAIR open in WHT (93) wire between washer pump connector C187 and fuse block. Test lamp lights. GO to step 2. Connect a test lamp from WHT (93) wire to PNK (94) wire at washer pump connector C187. Test lamp lights. REPLACE washer pump. Test lamp does not light. GO to step 3. Connect a fused jumper from PNK (94) wire at pulse wiper control module connector C207 to ground. Washer motor does not pump. LOCATE and REPAIR open in PNK (94) wire between washer pump connector C187 and pulse wiper control module connector C207. Washer motor pumps. GO to step 4. Washer motor does not pump. LOCATE and REPAIR open in PNK (94) wire between pulse wiper control module connector C207 and pulse wiper switch connector C204. Washer motor pumps. GO to step 5. Washer motor does not pump. REPLACE wiper switch. Washer motor pumps. LOCATE and REPAIR open in BLK (150) wire between wiper switch connector switch and ground G200. Place ignition to RUN or ACC and pulse wiper/washer switch to WASH. Connect a test lamp from WHT (93) wire at washer pump connector C187 to ground. Connect fusible jumper from PNK (94) wire at wiper switch connector C204 to ground. Connect a fusible jumper from BLK (150) wire at wiper switch connector C204 to ground. WASHER MOTOR DOES NOT SHUT OFF TEST 1. 2. RESULT ACTION Place ignition in RUN or ACC and wiper switch to WASH. Disconnect wiper switch connector C204. Washer motor stops pumping. REPLACE wiper switch. Washer motor pumps. GO to step 2. Disconnect wiper control module connector C207. Washer motor stops pumping. REPLACE pulse wiper control module. Washer motor pumps. LOCATE and REPAIR short to ground in PNK (94) wire between pulse wiper control module connector C207 and washer pump connector C187. WINDSHIELD WIPERS AND WASHERS A-51 PULSE HOT IN ACCY OR RUN 193-.8 WHT I WIPER 25 AMP 193-.S WHT I WINDSHIELD WIPER MOTOR C188 8917544 PULSE WIPER CONTROL MODULE C189 8917548 WINDSHIELD WASHER PUMP l/P _ A-52 WINDSHIELD WIPERS AND WASHERS PULSE : 94 29 15 9 39 14 33 12 J 93 11 : 18 120 : 24 30 919 I1n 420 440 439 806 39 _J m o g S201 (SEE PAGE 17) PULSE WIPER, WASHER SWITCH (COLUMN MOUNTED) CIRCUIT OPERATION DIAGNOSIS - START AND CHARGE PRELIMINARY CHECKS: START When the Ignition Switch is moved to the START position, battery voltage is applied to the Starter Solenoid. Both solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the Starter Motor. The windings work together magnetically to pull in and hold in the Plunger. The Plunger moves the Shift Lever. This action causes the Starter Drive Assembly to rotate as it engages the Flywheel ring gear on the engine. At the same time, the Plunger also closes the solenoid switch contacts in the Starter Solenoid. Full battery voltage is applied directly to the Starter Motor and it cranks the engine. Drive Assembly to disengage and Solenoid Switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off. As soon as the Solenoid Switch contacts close, voltage is no longer applied through the Pull-In Winding, since battery voltage is applied to both ends of the windings. The Hold-ln Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, and Drive Assembly Solenoid Switch contacts in place to continue cranking the engine. This Generator’s regulator uses digital techniques to supply the Rotor current and thereby control the output voltage. The Rotor current is proportional to the width of the electrical pulses supplied to it by the Regulator. When the Ignition Switch is placed in RUN, narrow width pulses are supplied to the Rotor, creating a weak magnetic field. When the engine is started, the Regulator senses Generator rotation by detecting AC voltage at the Stator through an internal wire. Once the engine is running the Regulator varies the field current by controlling the pulse width. This regulates the Generator output voltage for proper battery charging and electrical system operation. When the Ignition Switch is released from the START position, battery voltage is removed from the PPL (6) wire and the junction of the two windings. Voltage is applied from the Motor contacts through both windings to ground at the end of the Hold-ln Winding. However, the voltage applied to the Pull-In Windings is now opposing the voltage applied when the winding was first energized. The magnetic fields of the Pull-In and Hold-ln Windings now oppose one another. This action of the windings, with the help of the Return Spring, causes the Starter Turn headlamps and dome lamps ON and place ignition in START. If lamps go dim or go out, check battery for correct charge. If battery charge is CHARGE The Generator provides voltage to operate the vehicle’s electrical system and to charge its Battery. A magnetic field is created when current flows through the Rotor. This field rotates as the Rotor is driven by the engine, creating an AC voltage in the Stator windings. The AC voltage is converted to DC by the rectified bridge and is supplied to the electrical system at the Battery terminal. insufficient, refer to Section 6D of the 1991 R/V,P Light Truck Service Manual. If battery has sufficient charge, use the following procedures. ENGINE DOES NOT CRANK AND STARTER SOLENOID DOES NOT CLICK TEST 1. RESULT ACTION Place transmission in PARK (auto) or depress clutch pedal for man. trans. Connect a voltmeter from PPL (6) wire at starter solenoid to ground. Turn ignition switch to START position. Battery voltage. GO to step 2. No voltage. GO to step 3 for man. trans. GO to step 5 for auto, trans. Connect a voltmeter from PPL (6) wire to starter mounting bolts. Battery voltage. REPLACE starter solenoid Less than battery voltage. CLEAN starter motor mounting bolts, starter motor, and mounting surface. Disconnect clutch start switch connector C237. Connect voltmeter from YEL (5) wire at clutch start switch connector C237 to ground. Ignition switch must be in START position. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in YEL (5) wire between the clutch start switch and the ignition switch. If wire is in good condition, GO to step 5. Depress clutch and put transmission in neutral. Apply parking brake. Connect a fused jumper from YEL (5) to PPL (6) at clutch start switch connector C237. Turn ignition switch to START position. Engine cranks. REPLACE clutch start switch. Engine does not crank. LOCATE and REPAIR open in PPL (6) wire from clutch start switch to starter solenoid. 5. With ignition switch OFF, connect a voltmeter from RED (2) wire at ignition switch connector C209 to ground. Repeat step except connect from RED (3) wire at ignition switch connector C210 to ground. Battery voltage. REPLACE ignition switch. No voltage. REPLACE and REPAIR open in RED (2) wires and fusible link at junction block. 2. 3. 4. START AND CHARGE A-53 STARTER SOLENOID CL CKS, ENGINE DOES NOT CRANK OR CRANKS SLOWLY 1. 2. 3. ACTION RESULT TEST Remove CRANK and ECM 1 fuses. Connect a voltmeter to positive and negative battery terminals. Turn ignition switch to START. Voltage reading greater than 9.6 volts after 15 seconds cranking. GO to step 2. Voltage less than 9.6 volts after 15 seconds cranking. PERFORM a Battery Load Test. Refer to Section 6D in 1991 R/V, P Light Truck Service Manual. Connect a voltmeter from negative battery terminal to engine block. Less than .5 volts. GO to step 3. More than .5 volts. REPLACE negative battery cable. Less than .5 volts. REPAIR starter motor. More than .5 volts. REPLACE positive battery cable. Connect a voltmeter from positive battery terminal to starter solenoid terminal at BLK (2) wire. B A T T E R Y IS U N D ER C H A R G E D O R O V ER C H A R G E D RESULT TEST 1. 2. Connect voltmeter from RED (2) wire at generator to ground. Reconnect generator connector C106 and terminal. Have all accessories turned off and engine running at fast idle. Connect voltmeter from battery terminal on generator to ground. ACTION Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in RED (2) wire and fusible link from generator to junction block. Reading of 13-16 volts. PERFORM Generator Bench Test. Refer to Section 6D in the 1991 R/V, P Light Truck Service Manual. Reading of less than or greater than 13-16 volts. REPAIR generator. A-54 START AND CHARGE RPO CODES L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, ViN K L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE M20 - MAN TRANS, 4-SPD MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE C203 12066261 2-8.0 BLK/RED START AND CHARGE A-55 GASOLINE ENGINE RPO CODES LH 6. 6.2L (378 CU. IN.) V8 DIESEL ENGINE VIN C LL4 - 6.2L (378 CU. IN.) V8 DIESEL ENGINE VIN J M20 - MANUAL 4-SPEED TRANSMISSION MT1 - AUTOMATIC 3-SPEED TRANSMISSION E D fp E I OS] QT) firiU j 4i91 H r iQ O I 25-.8 BRN | -f~ — s is ’J O O ODnCD m llD D LH BATTERY C203 12066261 STARTER MOTOR o o l/P CLUSTER CONNECTOR (SEE PAGE 103) l/p ID 94 29 15 9 39 14 33 12 93 11 J 18 24 30 5 } 3 1 39 L 3»] r 2 1 820 4 ) 508 25 50 : 3 35 2 || 93 97 439 : 91 92 6 I V 12020184 C100 12045896 C106 START ■ r----- N— * '! i----- SHEET RIGHT BANK LEFT BANK METAL GLOW PLUGS GLOW PLUGS GROUND GROUND GROUND G111 G114 G113 >j /f * ' !■ -■ • -m • a -i Q: GLOW PLUGS CONTROLLER (SEE PAGE 84) vS= -< ) 2-3.0 BLU (FUSIBLE LINK) I 2-.8 BLK/RED I m | 2-.8 RED — eT c) ^ CLUTCH CLUTCI START SWITCH (MAN TRANS ONLY) A-56 START AND CHARGE DIESEL ENGINE RPO CODES L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN N L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE NA4 - EMISSION SYSTEM, ABOVE 8500 GVW CIRCUIT WIRE SIZE NO. COLOR CAVITY DESCRIPTION 465 .8 DK G R N /W H T 435 .8 GRA A1 A2 A3 A4 419 439 *4 2 2 .8 .8 .8 B R N /W H T PNK/BLK TAN/BLK A5 A6 A7 452 450 .8 .8 BLK BLK/W HT A11 A12 FUEL P U M P RELAY DRIVE N O T USED N O T USED EGR S O LEN O ID (L 0 5 ) EVRV (L 0 5 W ITH NA4, L 0 5 CAN ADIAN A N D L19) SYSTEM C H E C K LAMP 12V IG N ITIO N FUSED T O R Q U E C O N V E R TE R C LU TC H (M D8) SER IA L DATA A SSEM BLY LINE D IA G N O S TIC LINK SPEED S EN SO R (L 0 5 , L19 W IT H O U T RW AL) DRAC M O D U LE (L 0 5 , L19 W ITH RW AL) 5V R E TU R N B SYSTEM R ETURN 440 120 453 .8 .8 .8 ORN TA N /W H T BLK/RED 430 .8 PPL/W HT 485 59 .8 .8 BLK DK G RN *4 3 4 .5 O RN /B LK B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 12V BATTERY FUSED ELEC FUEL PU M P FUSED FEED DIS TR IB U TO R REF LOW N O T USED DIS TR IB U TO R REF H IG H N O T USED SPA RK RETARD C O N TR O L AIR C O N D ITIO N N O T USED PARK /N EU TR A L S W ITC H N O T USED N O T USED 461 451 437 .8 .8 .8 ORN W H T/B LK BRN A8 A9 A10 *A U T O TRA NS ONLY ELEC TR O N IC C O N TR O L M O DULE C O N N E C T O R CIRCUIT WIRE SIZE NO. COLOR CAVITY G R N /B LK G R N /W H T B L U /W H T BLU/BLK BLU C1 C2 C3 C4 C5 C6 C7 444 443 441 4 42 *4 46 .8 .8 .8 .8 .8 LT LT LT LT LT 806 410 432 .8 .8 .8 PPL7WHT YEL LT G RN 417 416 .8 .8 DK BLU GRA 440 .8 O RN 551 455 .8 .8 TA N /W H T PPL 423 4 24 413 412 .8 .8 .8 .8 WHT TA N /B L K TAN PPL 468 .8 DK GRN DESCRIPTION C8 C9 C 10 C11 C 12 C 13 C 14 C 15 C 16 N O T USED N O T USED S TEPPER C O IL B LO W S TEPPER C O IL B H IG H S TEPPER C O IL A H IG H S TEPPER C O IL A LO W A /C C O N T R O L (4TH GEAR D IS C R E TE (L05 W IT H M D 8) N O T USED C R A N K SIG N A L (FU SED) C O O L A N T TE M P E R A TU R E M AP S E N S O R N O T USED TP S E N S O R 5V S E N S O R R E FE R E N C E N O T USED 12V BATTERY FUSED D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 SYSTEM G R O U N D 5V R E TU R N A N O T USED HEI S PA R K T IM IN G HEI BYPASS OXYG EN S E N S O R LO W (G R O U N D ) OXYG EN S E N S O R HIG H N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED IN JE C TO R B (2) DRIVE N O T USED IN JE C TO R A (1) DRIVE 467 .8 DK BLU *A U T O TR A NS O NLY E LE C TR O N IC C O N T R O L M O D U LE C O N N E C T O R ELECTRONIC CONTROL MODULE PINOUTS A-57 GASOLINE ENGINE 43S-.8 PNK/BLKI ECM B 10 AMP A-58 ELECTRONIC CONTROL MODULE (ECM) INPUTS - GASOLINE ENGINE RPO CODES 439-.8 PNK/BLK L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE 7.4L (454 CID) V8 GAS ENGINE, VIN N MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE I419-.8 BRN/WHT I ♦ SERVICE ENGINE SOON LAMP (SEE PAGE 104) ECM CONNECTORS CRANK SIGNAL (FUSED) (SEE PAGE 55) ALDL C206 12020043 ENGINE GROUND G110 ELECTRONIC CONTROL MODULE (ECM) A-59 INPUTS - GASOLINE ENGINE v A A W A A /W W f < HOT AT ALL TIMES < J,W W V W V W V S 422-. 8 TAN/BLK I 439-.S PNK/BLK . ECM B 10 AMP EVRV (L19) ENGINE GROUND G115 A-60 ELECTRONIC CONTROL MODULE (ECM) OUTPUTS - GASOLINE ENGINE RPO CODES L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K M20 - MAN TRANS, 4-SPD. 119 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N 444-.S LT GRN/BLK | | 439-.S PNK/BLK I 440-.8 ORN 820-.8 PPL/WHT HANDLING MODULE + 12064770 E w m ' j i ^ 4 1 9 |4 5 0 | 451 | 4 3 7 |4 6 l] j SERVICE ENGINE |434|822] 821|696| 33 G H J 12064769 SOON LAMP (SEE PAGE 105) A 422-.S TAN/BLK ELECTRONIC CONTROL MODULE (ECM) OUTPUTS - GASOLINE ENGINE A-61 C O LO R CAVITY D E S C R IP T IO N A1 A2 A3 A4 A5 A6 M AP S E N S O R TP S E N S O R C O O L A N T T E M P E R A T U R E S W ITC H N O T USED N O T USED A S S EM B LY LINE D IA G N O S T IC LINK CONNECTOR N O T USED E N G IN E SPE E D S E N S O R V SS FR O M D R A C M O D U L E A S S EM B LY LINE D IA G N O S T IC LIN K CONNECTOR N O T USED TP S E N S O R A N D M AP S N E S O R 5V R E FE R E N C E C IR C U IT NO. W IR E SIZE 4 32 4 17 4 10 .8 .8 .8 LT G RN D K BLU YEL 451 .8 W H T/B LK 121 4 37 4 88 .8 .8 .8 W HT BRN LT G RN A7 A8 A9 A 10 4 16 .8 G RA A11 A 12 B1 B2 B3 B4 B5 B6 B7 B8 B9 B 10 B11 B12 NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT NOT USED USED USED USED USED USED USED USED USED USED USED USED E LE C TR O N IC C O N T R O L M O D U L E C O N N E C T O R CIRCUIT WIRE SIZE NO. COLOR 452 150 .8 .8 BLK BLK *4 2 2 421 .8 .8 T A N /B L K D K B LU /W H T 435 697 538 .5 .8 .8 GRA LT BLU D K G RN 439 .8 P N K /B LK 440 .8 ORN CAVITY DESCRIPTION C7 C8 C9 C 10 C11 C12 C 13 C 14 C 15 C 16 SYSTEM G RO UND SYSTEM G RO UND NOT USED NOT USED TO RQ UE CO N VER TER C LU TC H COLD ADV A N C E /G LO W PLUG TIM ER IN H IB IT RELAY NOT USED NOT USED NOT USED EGR DIAG NO STIC C O N N E C T O R EGR DUM P S O LEN O ID EPR VALVE SO LEN O ID NOT USED 12V IG NITIO N FUSED NOT USED 12V BATTERY FUSED D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 NOT NOT NOT NOT NOT NOT NOT NO T NOT NOT NOT NOT NOT NOT NOT NOT C1 C2 C3 C4 C5 C6 USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED USED *A U T O TR A NS O NLY E LE C T R O N IC C O N T R O L M O D U L E C O N N E C TO R A-62 ELECTRONIC CONTROL MODULE PINOUTS DIESEL ENGINE GAGE/IDLE 20 AMP 39-.8 PNK/BLK r 531-.8 LT GRN/BLK | COLD ADVANCE CONTROL 1531 A • 531-.8 LT GRN/BLK S121 m LL C167 2977253 538-.5 DK GRN I 421-.8 DK BLU/WHT 1397-.8 LT BLU ■ I )7 -.8 LT BLU I ------------------------ 1 - 150-.8 BLK I 150-1.0 BLK ■ r j q C193 S122 150-. 8 BLK ; (SEE PAGE 18) I 531-.8LT GRN/BLK V 697 .8 LT BLU I ------------------------------i - EGR DUMP 39-.s p n k /b lk m m r 435-.8 GRA EGR VALVE J H T ^ j^ m r 1 | 39-.S PNK/BLK * i^ r J V - I v ? z Q. CO C194 ERR VALVE K 39 / T \ 12015?Z6 a 39-.8 p n k /b lk mht jm m 53S-.8 DK GRN i = CD - r CD \ CD S? z CL CD £ z £ z w i'> CL CO 03 vj J |r _ 39-.S PNK/BLK a. CO 538-.8 DK GRN V^/ WATER IN FUEL SENSOR 538 ) (SEE PAGE 87) S109 • k r _____ m aw 39-.s p n k /b lk COLD ADVANCE FAST IDLE TEMPERATURE SWITCH (SEE PAGE 87) 531-.8LT GRN/BLK ENGINE GROUND A-64 ELECTRONIC CONTROL MODULE (ECM) OUTPUTS DIESEL ENGINE GLOW PLUG CONTROLLER 150-.8 BLK r , l 439-.S PNK/BLK 439-.S PNK/BLK I ELECTRONIC CONTROL MODULE (ECM) A-65 OUTPUTS DIESEL ENGINES CIRCUIT WIRE SIZE NO. COLOR CIRCUIT WIRE NO. SIZE COLOR CAVITY GRA PPL FU E L P U M P RELAY D RIVE S O LE N O ID B D R IV E R S O LE N O ID A D R IV E R T C C D RIVER N O T USED N O T USED S YS TE M C H E C K LAM P N O T USED N O T USED N O T US E D EVR V S O LE N O ID BRAKE S IG N A L 439 450 551 4 16 417 441 442 4 44 443 432 461 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 P N K /B LK B LK /W H T T A N /W H T G RA D K BLU LT B LU /W H T LT B LU/BLK LT G R N /B L K LT G R N /W H T LT G RN ORN RED D K BLU PNK LT BLU D K G R N /Y EL LT B LU /W H T B LK /R ED D K B LU /W H T G R A /R E D BRN D K G RN B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B 12 N O T USED P R E S S U R E S W ITC H M A N IF O L D C P R E SS U R E S W ITC H M A N IF O L D B P R E SS U R E S W IT C H M A N IF O LD A O U T P U T S P E E D H IG H O U T P U T S P E E D LO W FO R C E M O T O R LO W FO R C E M O T O R H IG H IN P U T S PE E D H IG H IN P U T S PE E D LO W V SS (W /O RW AL) D R A C (W / RW AL) AIR C O N D IT IO N IN G 413 412 468 467 .8 .8 .8 .8 TAN PPL D K G RN D K BLU 440 455 452 474 4 96 451 1 20 .8 .8 .8 .8 .8 .8 .8 ORN PPL BLK GRA D K BLU W H T/B LK T A N /W H T D2 D3 D4 D5 D6 D7 WHT TA N /B LK BLK/RED P P L /W H T BLK/YEL YEL D8 D9 D 10 D11 D 12 D 13 D 14 D 15 D 16 .8 .8 .8 .8 D K G R N /W H T YEL/B LK LT G R N T A N /B L K 419 .8 B R N /W H T 435 4 20 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 DESCRIPTION A1 A2 A3 A4 A5 A6 A7 A8 A9 A 10 A11 A 12 4 65 1223 1222 422 1226 1225 1224 1232 1233 1229 1228 1230 1231 4 37 59 CAVITY P O W E R TR A IN C O N T R O L M O D U L E C O N N E C T O R 423 424 4 53 4 30 1 22 7 410 .8 .8 .8 .8 .8 .8 C1 C2 C3 C4 C5 C6 C7 C8 C9 C 10 C11 C 12 C13 C14 C15 C16 D1 DESCRIPTION 12V IG N ITIO N FUSED SYSTEM G R O U N D SYSTEM G R O U N D 5V SEN SO R R E FE R E N C E TPS STEPPER C O IL A H IG H STEPPER C O IL A LO W STEPPER C O IL B LO W STEPPER C O IL B H IG H MAP SERIAL DATA N O T USED OXYGEN SEN SO R G R O U N D OXYGEN SEN SO R INJEC TO R B DRIVER INJEC TO R A DRIVER 12V BATTERY FUSED S ENSO R G R O U N D SEN SO R G R O U N D 5V SEN SO R RE FE R E N C E K N O C K SIGNAL ALDL ELECTRIC FUEL P U M P FEED FUSED N O T USED NO T USED NO T USED HEI SPA RK T IM IN G HEI BYPASS DISTRIBUTO R R E FE R E N C E LO W DISTRIBUTO R R E FE R E N C E H IG H TR A N SM IS S IO N TE M P E R A TU R E CO O LANT TE M P E R A TU R E P O W E R TR A IN C O N T R O L M O D U LE C O N N E C TO R A-66 POWERTRAIN CONTROL MODULE PINOUTS CIRCUIT WIRE SIZE NO. COLOR 1 224 1 225 1 226 1 223 1 22 2 451 .8 .8 .8 .8 .8 .8 PNK DK BLU RED YEL/BLK LT G R N W H T/B LK 440 .8 O RN 59 4 20 4 22 488 1 23 3 1232 .8 .8 .8 .8 .8 .8 DK G R N PPL/BLK TA N /B LK LT G R N DK G R N /Y E L LT BLU CAVITY DESCRIPTION A1 A2 A3 A4 A5 A6 A7 A8 A9 A 10 A11 A 12 N O T USED N O T USED P R E SS U R E S W ITC H M A N IF O LD A P R E SS U R E S W ITC H M A N IF O LD B P R E SS U R E S W ITC H M A N IF O LD C S O LE N O ID B D R IV E R S O LE N O ID A DR IVER ALDL N O T USED N O T USED N O T USED 12V BATTERY FUSED B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 N O T USED N O T USED A IR C O N D IT IO N IN G BRAKE S IG N A L TCC N O T USED N O T USED N O T USED N O T USED SER IA L DATA O U TP U T SPE E D S E N S O R LO W O U TP U T SPE E D S E N S O R H IG H CIRCUIT WIRE SIZE NO. 150 150 4 52 4 16 .8 .8 .8 .8 COLOR BLK BLK BLK G RA CAVITY C1 C2 C3 C4 C5 C6 1 22 8 439 .8 .8 R E D /B LK P N K /B LK 4 37 1231 1232 .8 .8 .8 BRN DK B LU /W H T LT BLU 121 452 4 17 .8 .8 .8 WHT BLK D K BLU 1 227 4 32 .8 .8 BLK/YEL LT G RN 1229 .8 LT B LU /W H T TR A N S M IS S IO N C O N T R O L M O D U L E C O N N E C T O R DESCRIPTION C7 C8 C9 C 10 C11 C 12 C 13 C 14 C 15 C 16 SYSTEM G R O U N D SYSTEM G R O U N D SENSOR GROUND 5V S E N S O R R E FE R E N C E N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED N O T USED F O R C E M O T O R H IG H 12V IG N IT IO N FUSED D1 D2 D3 D4 D5 D6 D7 D8 D9 D 10 D11 D12 D13 D14 D 15 D 16 N O T USED VSS IN P U T S PE E D LO W IN P U T SPE E D H IG H N O T USED E N G IN E SPEED SENSOR GROUND TP S E N S O R N O T USED N O T USED N O T USED T R A N S M IS S IO N TE M P E R A TU R E M AP S E N S O R N O T USED N O T USED FO R C E M O T O R H IG H T R A N S M IS S IO N C O N T R O L M O D U LE C O N N E C T O R TRANSMISSION CONTROL MODULE (TCM) A-67 DIESEL ENGINES WSAAAW^WWVW W W W W W W \yf S HOT AT ALL TIMES < J ^ HOT IN START OR RUN ^ W w w vvw s ECM B 10 AMP COOLANT TEMPERATURE SENSOR OXYGEN SENSOR OUTPUT SPEED SENSOR (4WD ONLY) INPUT SPEED SENSOR A-68 POWERTRAIN CONTROL MODULE (PCM) INPUTS - GASOLINE ENGINE W/HD 4-SPD., AUTO TRANS W/OVERDRIVE G110 ENGINE GROUND TRANSMISSION ENGINE GROUND G115 iv - jm ^ * r m m r m m ar ^m w m tm ' w jm m r jm m r M m m r 450-.8 b lk / w h t ' ^ 551 -.8 t a n / w h t mmmr m m r ®i A/C (SEE PAGE 94) POWERTRAIN CONTROL MODULE (PCM) A-69 INPUTS - GASOLINE ENGINE W/HD 4-SPD., AUTO TRANS W/OVERDRIVE 439-.8 PNK/BLX I ECM B 10 AMP EVRV ELECTRONIC SPARK TIMING INJ-2 INJ-1 FUEL PUMP OIL PRESS SWITCH FUEL PUMP RELAY C100 12020183 I 440-1.0 ORN A-70 POWERTRAIN CONTROL MODULE (PCM) OUTPUTS ■ GASOLINE ENGINE W/HD 4-SPD., AUTO TRANS W/OVERDRIVE k /W V W W W 'M < k /W W W W W HOT AT ALL TIMES < I a A/WWWWVn ECM B 10 AMP \ «, WvVVWWVVWVW HOT IN START > / W W V W W V ' ECM 1 CRANK 3 AMP r S HOT IN START OR RUN < Ir 'W V W W V W V V n 439-.8 PNK/BLK 439-.8 PNK/BLK I _ i 1440*1.0 ORN I TP SENSOR r439*.8 PNK/BLK ■ r. r 1223-.8 YEL/BLK 1440*1.0 ORN 439-.8 PNK/BLK | _ c 11226-.8 RED I 11225-.8 DK BLU ■ -452 C •417 B 1 1224- 8 P N K H 1452-.S BLK I ■ 1 2 1 -.8 W H T H I I417-.8 DK BLU 1452-.8 BLK I 1416-.8 GRA I 416 | 420-.8 PPL/BLK m C134 12052843 r - 422-.S TAN/BLK r I 417-.8 DK B L U M 1229-.8 LT BLU/WHT I ^ 1233-.8 DK GRN/YEL I 11232-.8 LT BLU I 11222-.8 LT GRN I I 416-.8 GRA I • ■ I 452- 8 BLK I S122 (SEE PAGE 18) | 150-.8 BLK | • 1230 ■ I 150-.8 BLK I ' 1227-.8 BLK/YEL m -1231 M230-.8 DK BLU/WHT i C173 12078084 INPUT SPEED SENSOR a 1230-.8 GRA/RED M ■ 1231-.8 DK BLU/WHT F 11231-.8 GRA/REDBT r 452 1228-.8 RED/BLK A I452-.8 BLK I 0 121 B 1121-.8 W H Tl m LU C175 12015792 ENGINE SPEED SENSOR 3 m H -j® n 5 O * Q CO j I •1233 11233-.8 DK GRN/YEL ■ -1232 OUTPUT SPEED SENSOR C172 12084690 11232-.8 LT BLU I TRANSMISSION CONNECTOR 12084435 A-72 TRANSMISSION CONTROL MODULE (TCM) DIESEL ENGINE 439-.S PNK/BLK • | i-139 h r Ul s I 92 I 91 I C100 12020183 ENGINE GROUND G110 W sM AW M VW Vf RPO CODES S HOT IN START OR RUN Z MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE "w w v w v w w v v a * GAGE/IDLE 20 AMP GT101 12064740 422-.8 TAN/BLK 446-.S LT BLU i B ©01 £ A 1 14651 D »1 2 14531 3 1------ 1 4 |430l 5 L 1 6 f4 8 5 l 7 S O 8 1 1 9 [434110 BRAKE SWITCH 1'" “ 1 |___ | P»35l 14191 14 39 1 [4 2 2 * f46T1 f4 5 fl |4 3 7| (M D 8 ONLY) £ z CL I I 11 I452I I___ | 12 [450J ECM CONNECTORS ______i________ i (SEE PAGE 116) 139-.8 PNK/BLK S202 (SEE PAGE 27) e I RWAL DIODE ARRAY MODULE I - O D 01 CN to * C ILJ C215 G H J K C203 12020043 ( I ALDL L I : 18 120 : 24 30 9 I 19 | 140 2 39 31 3 3> r 50 436 93 97 91 92 35 : 120 2 422 V 6 o o A-74 TRANSMISSION CONVERTER CLUTCH (TCC) DETENT SOLENOID 5.7L V8 GASOLINE ENGINE I 422-.S TAN/BLK I A O to * S211 z Ui > § O AC 0 z Ui > IT * C289 12066130 822-.8 LT GRN/BLK I A 821-.8 PPL/WHT □SDH GT101 12064740 I 437-.S BRN RWAL CONTROLLER (SEE PAGE 116) I 696*.8 WHT H i i (L05 WITH M20) C200 CRUISE CONTROL (SEE PAGE 124) [ 150-.8 BLK (LL4 ONLY) fc S215 (SEE PAGE 17) I ______ CD 422 696 461 S122 (SEE PAGE 116) • 436 j c ____ 436 150-.8 BLK ____ 451 ALDL CONNECTOR C206 12020043 CD f C100 12020183 ENGINE GROUND G110 450/151) ^ (450/151 mgr ^450-.8 45o-.seBLK/WHT * \ FUEL PUMP CYCLE RELAY (SEE PAGE 79) ENGINE GROUND G115 DIGITAL RATIO ADAPTER CONTROLLER (DRAC) MODULE A-75 RPO CODES yvwwwwwvv/ < GAGE/IDLE 20 AMP ^w w w vw w w HOT IN START OR RUN < m w v v w v v v w ^ ECM 1 ? L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K S HOT IN START OR RUN ^ ^ L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N ^MVVNAVWWV^A 10 AMP I 439-.S PNK/BLK 439-.8 PNK/BLK I f 39-.S PNK/BLK o | 423-.8 WHT I i 430-.8 PPL/WHTI 424-.S TAN/WHT 453-.B PPL/WHT _ _ i ^ ( ) — _ T C133 GT101 424-.8 TAN/WHT 12064740 121-.8 WHT 3-3.0 PNK TACHOMETER °? 139-.8 PNK/BLK ■ EVRV SOLENOID (L19) IGNITION SWITCH (SEE PAGE 11) (SEE PAGE 60) AIR SWITCH SOLENOID (UTILITY ONLY) (SEE PAGE 60) EGR SOLENOID (L05 ONLY) (SEE PAGE 60) 439-.Q PNK/BLK ■ 439-.B PNK/BLK I A-76 IGNITION GASOLINE ENGINE HYBRID FUNCTION ESC (SEE PAGE 58) I 439-.8 PNK/BLK I ECM 1 10 AMP ECM CONNECTORS THROTTLE BODY INJECTOR A-77 GASOLINE ENGINE RPO CODES 440-1.0 ORN I vAW AM AM M < L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N HOT AT ALL TIMES < . HOT IN START O R RUN >VVVW\AMMN 39-.8 PNK/BLK* ECM CONNECTOR ECM B 10 AMP GAGE/IDLE 20 AMP iv n v r B FUEL PUMP CYCLE RELAY (HOT FUEL HANDLING MODULE) A 1465 Ip r f l2 0 l 2 1------ 1 14531 3 L Z 3 □ 4 [435] [4301 5 14191□ 6 1439] f4 8 5 l 7 E H ] 1 59 1 8 J461 | [~ 1 9 I 451J [434110 14371 IDLER AIR CONTROL FRAME (LI 9) IGNmON SW FUEL PUMP FUSED GROUND ito G E l C Z 3 e | cQ D b C D i— | g 450 AI 12° I i I 11 i 452J I___ I 12 I 450 h 120-.8 GRA (SUBURBAN ONLY) 120-1.0 TAN/WHT JM Ih I C194 12045688 C161 12078082 ALDL (SEE PAGE 59) J 450*.8 BLK/WHT. I 440-.8 ORN I I 465-.8 DK GRN/WHT , % S215 (SEE PAGE 79) 120-.8 GRA I IDLE AIR CONTROL ACTUATOR 441-.8 LT BLU/WHT | 441-.8 LT BLU/WHT I 443-.8 LT GRN/WHT" 443-.S LT GRN/WHT 442-.8 LT BLU/BLK A 442-.8 LT BLU/BLK ■ 444-.S LT GRN/BLK I 444-.8 LT GRN/BLK . 0-05) STEPPER MOTOR DRAC (SEE PAGE 75) * 450-.8 BLK/WHT 551-.8 TAN/WHT 441 ENGINE GT100 12064740 442 fYYY^ I.. 413-.8 TAN I 443 444 : 94 29 15 9 39 14 33 12 806 | 439 120 140 I 93 C161 12015796 436 FUEL PUMP OIL PRESSURE SWITCH 422 11 L J ( 50 : 18 120 : 24 30 97 1 93 | 3 2 I 420 440 439 806 9I 19 | 39 140 120 31 3 50 436 3»rJ 35 2 93 97 422 91 92 6 | : \ GE3 «*S139 C100 12020183 440-.8 ORN I 1120-1.0 G R A i C100 12020184 ECM CONNECTOR FUEL GAGE 120-1.0 GRA I C115 12065401 ’ (SEE PAGE 108) 440-1.0 ORNI FUEL PUMP PRIME 120-1.0 TAN/WH1 I C409 12059473 RWAL (SEEPAGE 116) C160 2977253 ELECTRIC FUEL PUMP FUEL GAGE SENDING UNIT S140 . 120-1.0 TAN/WHT 30-.8 PNK I 450-.8 BLK/WHT I C101 12020099 FUEL PUMP RELAY 450-.8 BLK/WHT I v ^Jl C148 12052287 A-78 FUEL CONTROL AND IDLE AIR CONTROL GASOLINE ENGINE ENGINE GROUND O G110 ^ ENGINE GROUND G115 BLU OR PPL^ OR LT GRN FRAME GROUND G409 J 3Q-.8 PNK/BLK 39-. 8 PNK/BLK (FUEL PUMP CYCLE RELAY HOT FUEL HANDLING MODULE) GAGE/IDLE 20 AMP a =! ________I GROUND.- 450 c 9 IGNITION SWITCH - 4 39 FUEL PUMP FUSED - • 120 GT 101 S117 (SEE PAGE 17) o o 12064740 c r --------------------------------- I bCZI CI3 cziH S T r - ' M I □ O f T ’ <~ r « l----- 1 I----- 1SI v: h pm ^ | ^ | ------------------------------------ S139 i r ^ 450-.8 BLK/WHT FUEL PUMP OIL PRESS SWITCH (SEE PAGE 60) \ \ I l ______ 0 C200 tar TBt jir— c r _ L \ »- I 12064770 l I 120-1.0 GRA 1 § || ■ 120-1 .O G R A M B ^ - l _____________ 12047886 1450-.8 BLK/WHT I r450-.8 BLK/WHT V . I w ------------ I - n 12045688 rm 120-.8 G RAI M -t-, I FUEL PUMP RELAY (SEE PAGE 60) —i I i | I I B A 14401 1 14651 2I I \ [4531 3 C D I I 4 [4351 [430l 5 E H } H I r I H \ I I I ECM CONNECTOR (SEE PAGE 27) m m ^ 1 4 5 0 - 8 BLK/WHT \ r (SEE PAGE 59) ^ ?* r- m DRAC ^45 0 -.8 BLK/WHT i (SEE PAGE 75) I450-.8 BLK/WHT I I n mO ” I 11 [4521 I 12 [ 450)1 l/P ^ ■ 4 5 0 - . 8 BLK/WHT ALDL • I 6 [Ml f~59~l 8 [4611 I I 9 IW l [4341 10 14371 _____________ ^m S215 ^ ^ CO ELECTRIC FUEL PUMP FUEL GAGE SENDING UNIT PARK/NEUTRAL SWITCH (SEE PAGE 59) T ENGINE k i r IS 1 i - —13 „ [LiJ i T 112 1 ( i 39 1120 I3 306 | 439 140 | J 35j "1 B ■1 6 92 | 91 | A 3 S C100 12020183 G110 ENGINE GROUND 15 39 14 (50/130> C 97 | 9 3 1 29 9 : 93 y))}DE 8g-p / 5 0 /2 5 ] ♦N m 94 33 F II 1 |422 2 Cl G 31 | | 436 | 50 | I2 H 440 | 420 | : 18 24 420 440 439 806 L 140 J 31 T (3 >I50 r 9735 120 93 12 11 9 A 19 91 92 450-.8 BLK/WHT 2 39 | 120 I jm w a w m jm 39-.s p n k /b lk 3 39-.S PNK/BLK 436 _______ ___ i FRAME GROUND G409 2 422 : 6 d I K P CO v = i 120-1.0 TAN/WHT Z 120-.8 TAN/WHT ______________________________________________ 120-.8 GRA“(SUBURBAN ONLY) \ 120-.8 GRA (SUBURBAN ONLY) WIRE COLOR CAN BE BLU, C100 12020184 PPL OR LT GRN A 120-1.0 TAN/WHT d 18 24 120 30 9 19 I 30-.8 PNK I C101 12020094 30-.5 PNK I FUEL GAGE (SEE PAGE 108) I 30-.8 PNK I HOT FUEL HANDLING A-79 GASOLINE ENGINES 39-.8 PNK/BLK ENGINE $___ I GAGE/IDLE 20 AMP o I 4S0~1 ( IG NITIO N SW FUEL PUM P FUSED GROUND C I 450 B[ FUEL PUMP RELAY U U a Ie 39 Q 39-.8 PNK/BLK I I )0 | | H 1 I V ------------------- 39-.S PNK/BLK 39-,8 PNK/BLK a 94 5* Dk 6 Ml 15 14 N 9 39 M 33 12 L 93 11 J r 2 420 440 439 806 39 L 140 120 31 3 m , r 50 436 35 2 93 97 422 91 92 6 j S202 (SEE PAGE 27) • l/P p — I r [/ (HOT FUEL HANDLING MODULE) ELECTRIC FUEL PUMP ASSEMBLY I (AUXILIARY RIGHT SIDE) 30-.8 PNK * 120-1.0 TAN/WHT _ _ ^ Q | 120-1.0 TAN/WHT ♦ FUEL TANK SELECTOR VALVE AND METER SWITCH C304 FUEL GAGE (SEE PAGE 108) FUEL TANK SELECTOR SWITCH 9 2 1 -1 .0 G R A 921-1.0 GRA 921-1.0 GRA 1 • 920-1.0 TAN 920-1.0 TAN ■ ■ S329 I 921-1.0 GRA IM *| LEF cT rJ p ? i 920-1.0 TAN H 3 930-.8 PNK/WHT 120-1.0 TAN/WHT 8 12010973 BUS BAR GROUND G201 to E L* 12015792 £ I w m m 30-. 8 PNK ■ ■ ■ VALVE 931-.8 PNK/BLK RIGHT C305 12020089 ELECTRIC FUEL PUMP (PRODUCTION LEFT SIDE) WIRE CAN BE BLU, PPL OR E C203A 8911256 A-80 AUXILIARY FUEL TANK AND FUEL TANK SELECTOR SWITCH GASOLINE ENGINE C302 C409 12059473 FRAME GROUND G409 DK GRN COLOR FRAME GROUND G410 15 FUEL GAGE (SEE PAGE 108) G201 BUS BAR GROUND G410 FRAME GROUND r\ (Q) (Q) ■=" •= ■ G409 FRAME GROUND AUXILIARY FUEL TANK AND FUEL TANK SELECTOR SWITCH A-81 DIESEL ENGINE WAIT INDICATOR DOES NOT FLASH OR FLASHES FOR THE INCORRECT AMOUNT OF TIME WHEN ENGINE IS BELOW NORMAL OPERATING TEMPERATURE CIRCUIT OPERATION The heating of the Glow Plugs is controlled by the Glow Plug Relay in the Glow Plug Controller. Battery voltage is applied to the relay contacts through the RED wire from the Junction Block. The relay is operated by a Solid-State Controller. The Controller responds to engine temperature and also to an Ignition Switch Start input. After the initial time period the relay will de-energized for five seconds then will cycle ON/OFF for approximately 10 seconds. When the Ignition Switch is turned to RUN, battery voltage is applied to the Enable Input of the Controller. The Glow Plug Relay within the Controller will be energized for approximately five seconds during which it applies voltage to the Glow Plugs and WAIT Indicator. After approximately 25 seconds the Controller will open the Glow Plug Relay and the heating of the plugs stops. If the engine is restarted while the engine is at normal operating temperature, the ECM will keep the relay contacts open so that no plug heating takes place. TEST NOTE: For 6.2L V8 diesel engines, ground DK BLU/WHT (421) wire at cold advance glow plug inhibit relay connector C108. RESULT Test lamp lights. GO to step 2. 1. Place ignition switch in RUN position. Connect test lamp from RED (2) wire at glow plug controller to ground. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire and fusible link from glow plug controller to junction block. 2. Test lamp lights. GO to step 5. Test lamp does not light. GO to step 3 for 6.2L engines. When the Glow Plug Controller receives the Start Input, the Glow Plugs and WAIT Indicator will cycle ON/OFF after the Ignition Switch is returned to RUN. DIAGNOSIS - GLOW PLUGS Connect a test lamp from LT GRN/BLK (531) wire for 6.2L or PNK (3) wire for 6.2L HD engines at glow plug controller connector C168 to ground. For 6.2L HD engines, LOCATE and REPAIR open in PNK (3) wire from glow plug controller to ignition switch. PRELIMINARY CHECKS: A check of the glow plug system should be performed before diagnostic procedures. With engine below normal operating temperature, turn ignition switch to RUN. The WAIT indicator should light. After approximately 10 seconds, the WAIT indicator must begin to flash for an additional 10 seconds and then go out. Turn ignition switch to OFF and then momentarily to START and return to RUN position. The WAIT indicator should flash for approximately 25 seconds and then go out. 3. With engine at normal temperature, turn ignition switch to RUN. The WAIT indicator should not flash for an 6.2L engine, but should flash for an 6.2L HD engine. 4. 5. A-82 GLOW PLUGS ACTION Connect a test lamp from each PNK/BLK (39) wire at cold advance glow plug inhibit relay connector C108 to ground. Connect a 10 amp fused jumper from DK BLU/WHT (421) wire at cold advance glow plug inhibit relay connector C167 to ground. Connect test lamp from LT GRN/BLK (531) wire at inhibit relay connector C108 to ground. Connect a test lamp from LT GRN/BLK (531) wire for 6.2L engines or PNK (3) wire for 6.2L HD engines to BLK (150) wire at glow plug controller connector C168. Test lamp lights. GO to step 4. Test lamp does not light. CHECK condition of GAGE/IDLE fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire from inhibit relay to fuse block. Test lamp lights. CHECK for open in DK BLU/WHT (421) wire from inhibit relay to ECM. If wire is good, problem is with ECM. Refer to Section 6E in the 1991 R/V, P Light Truck Service Manual. Test lamp does not light. CHECK for open in LT GRN/BLK (531) wire. If good, REPLACE cold advance glow plug inhibit relay. Test lamp lights. GO to step 6. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from glow plug controller to ground terminal G110. WAIT INDICATOR STAYS ON OR FLASHES WHEN ENGINE IS AT NORMAL OPERATING TEMPERATURE AND IGNITION SWITCH IN RUN POSITION (6.2 L DIESEL ENGINE ONLY) TEST RESULT ACTION WAIT INDICATOR DOES NOT FLASH OR FLASHES FOR THE INCORRECT AMOUNT OF TIME WHEN ENGINE IS BELOW NORMAL OPERATING TEMPERATURE ______________ TEST 6. 7. 8. 9. ACTION RESULT Connect test lamp from PPL/WHT (806) wire at glow plug controller connector C168 to ground. Move ignition switch to START position. Test lamp lights. GO to step 7. Test lamp does not light. LOCATE and REPAIR open in PPL/WHT (806) wire from glow plug controller to starter motor. Place ignition switch to OFF position. Connect test lamp from ORN (503) wires at glow plug controller to ground. Test lamp lights. REPLACE glow plug controller. Test lamp does not light. GO to step 8. Disconnect glow plug controller connector C168. Using a positive polarity ohmmeter, check continuity between ORN (503) or (509) wires and BLK (150) wires. Reading of 2 ohms or less. GO step 9. Reading greater than 2 ohms. LOCATE and REPAIR open in GRA (503)and (509) wires from glow plug controller connector C117 to glow plug harness splices S198 and S199. Connect glow plug controller connector. Connect test lamp from ORN (503) wires at glow plug controller to connector C168 to ground. Turn ignition switch momentarily to START and then release to RUN position. Test lamp cycles on and off for approximately 25 seconds then goes off. GO to step 11. Test lamp does not light or cycles for the incorrect time. REPLACE glow plug controller. Test lamp lights for all glow plugs. LOCATE and REPAIR open in ORN (503) or ORN/BLK (509) wires and fusible links from glow plug to controller. Test lamp does not light for one or more glow plugs. REPLACE glow plug(s) where test lamp did not light. 10. Remove all connectors from glow plugs. Connect one lead of test lamp to battery voltage and other lead to each glow plug. 1. Connect test lamp from each PNK/BLK (39) wire at cold advance glow plug inhibit relay connector C108 to ground. Test lamp lights. GO to step 2. Test lamp does not light. CHECK condition of GAGE/IDLE fuse. If fuse is good, LOCATE and REPAIR open from inhibit relay to fuse block. 2. Test lamp lights. CHECK for open in DK BLU/WHT (421) wire from inhibit relay to ECM. If wire is good, problem is with ECM. Refer to Section 6E in 1991 R/V, P Light Truck Service Manual. Test lamp does not light. REPLACE cold advance glow plug inhibit relay. Connect a fused jumper from DK BLU/WHT (421) wire at cold advance glow plug inhibit relay connector C108 to ground. Connect test lamp from LT GRN/BLK (531) wire at inhibit relay connector C108 to ground. GLOW PLUGS A-83 3108 11-32.0 BLK I 906-1.0 P P Li I 2-.Q BLK/RED ■ 2- 8 BLK/RED I RIGHT BANK GLOW PLUGS 3-3.0 PNK I + - RH BATTERY 1 + FUEL SHUTOFF SOLENOID ~ LH BATTERY FUSIBLE LINKS S198 509-5.0 ORN/BLKI H 509-2.0 GRA m (FUSIBLE UNK) ■ i 503-2.0 GRA ■ ■ ^ S199 FUSIBLE UNK) FUSIBLE UNKS S103 S197 503-1.0 ORN I 503-1.0 ORN I LEFT BANK GLOW PLUGS LEFT BANK SHEET GLOW PLUGS METAL GROUND GROUND G113 G111 RIGHT BANK GLOW PLUGS GROUND G114 6-3.0 PPL I 2-3.0 RED ■ • ■ S106 A-84 GLOW PLUGS 12-3.0 RED 1 RPO CODES LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J LH6 • ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C M20 • MAN TRANS, 4 SPD. 1806-1.0 PPL/WHTl COLD ADVANCE GLOW PLUG 531-.8 LT GRN/BLX " TIMER INHIBIT RELAY (LH6) (SEE PAGE 64) COLD ADVANCE CONTROL (LH6) (SEE PAGE 64) CLUTCH START SWITCH (M20 ONLY) (SEE PAGE 56) ENGINE GROUND G110 i/P GROUND (0 1 G200 ^ GLOW PLUGS A-85 DIAGNOSIS —DIESEL ENGINE FUEL CONTROLS CIRCUIT OPERATION The Diesel Fuel Filter System combines five functions into a single package: the fuel. When the switch is closed, battery voltage is applied to the heater form the GAGE/IDLE Fuse. 1. Heats diesel fuel to prevent wax-plugging of the filter. 2. Combines very small droplets of water in the fuel into larger drops and separates the water from the fuel. 3. Filters the diesel fuel. 4. Detects the presence of excess water in the fuel and 5. Provides a means to drain the water it has separated. The fuel then passes through the Primary and Secondary filters. Next the fuel flows through the water coalescer. Here the droplets of water in the fuel are combined into larger drops, the drops fall to the water reservoir in the filter. When the fuel flows from the Fuel Filter Assembly to the injection pump, it is clean and free of water. The Fuel Filter Assembly consists of the Fuel Heater, the Water In Fuel Sensor and a Filter. The Filter contains the "coalescer" (the device that combines small droplets of water into larger ones) and the filter/separator. An electric fuel pump delivers diesel fuel from the tank to the fuel filter. As fuel enters the filter, it passes first through the Fuel Heater. The heater contains a thermostatic switch. The switch opens or closes, to turn the heater off or on, depending on the temperature of The Solid-State Water In Fuel Sensor applies voltage to a Probe. When the Probe touches water, the Module closes a switch. This completes a circuit to ground to light the SERVICE FUEL FILTER indicator. A time delay circuit in the Water In Fuel Module grounds the indicator bulb briefly to test the bulb each time the system is turned on. PRELIMINARY CHECKS: CHECK condition of GAGE/IDLE fuse. If fuse is If fuse is in good condition, use the following blown, LOCATE and REPAIR source of overload, then diagnostic procedures. REPLACE fuse. FUEL HEATER DOES NOT OPERATE TEST 1. Disconnect fuel heater connector C196. Place ignition switch to RUN position. Connect a voltmeter from PNK/BLK (39) wire at fuel heater connector C196 to ground. 2. Connect a voltmeter from PNK/BLK (39) wire to BLK (150) wire at fuel heater connector C196. RESULT ACTION Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in PNK/BLK (39) wire from fuel heater to fuse block. Battery voltage. REPLACE fuel filter. No voltage. LOCATE and REPAIR open in BLK (150) wire from fuel sensor to ground terminal G110. SERVICE FUEL FILTER INDICATOR DOES NOT LIGHT BRIEFLY WITH IGNITION SWITCH TURNED TO RUN TEST 1. RESULT ACTION Disconnect water in fuel sensor connector C197 and place ignition switch in RUN. Connect a voltmeter from PNK/BLK (39) wire at fuel sensor connector C197 to ground. Battery voltage. GO to step 2. No voltage reading. LOCATE and REPAIR open in PNK/BLK (39) wire from fuel'sensor to fuse block. 2. Connect a voltmeter from PNK/BLK (39) to BLK (150) wire at water in fuel sensor connector C197. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in BLK (150) wire from fuel sensor to ground terminal G110. 3. Battery voltage. REPLACE fuel filter. No voltage. CHECK Service Fuel Filter lamp. If lamp is good, LOCATE and REPAIR open in YEL (508) wire. Connect a voltmeter from YEL (508) wire at water in fuel sensor connector C197 to ground. SERVICE FUEL FILTER INDICATOR LIGHTS WITH NO WATER IN FUEL TEST 1. Place ignition switch in RUN position. Disconnect water in fuel sensor connector C197. A-86 DIESEL ENGINE FUEL CONTROLS RESULT ACTION SERVICE FUEL FILTER indicator stays on. LOCATE and REPAIR short to ground in YEL (508) wire. SERVICE FUEL FILTER indicator goes out. REPLACE fuel filter. yvw w w w vw / < HOT IN START OR RUN ? m w vvvw w w ^ 39 I / . GAGE/IDLE 20 AMP * COLD ADVANCE FAST IDLE TEMPERATURE SWITCH 534 B #1 C102A a 2977373 534-.S DK GRN I 39-. 8 PNK/BLK FAST IDLE SOLENOID EGR DUMP VALVE (SEE PAGE 64) C100A EGRVALVE (SEE PAGE 6 4 )' 39-.8 PNK/BLK r . k M COLD ADVANCE TIMER EPR VALVE (SEE PAGE 64) ' . 39- 8 p n k /b lk jm m 39" 8 PNKyBLKWr S '• b | I a ^ 39-.s p n k /b lk 39 e PNK/BLK ^ I RELAY (SEE PAGE 64) | GENERATOR (SEE PAGE 12) V i I S I 22 (SEE PAGE 18) I U I \ CD £ * £ 2 CD WATER IN FUEL SENSOR S202 (SEE PAGE 27) n o r 39- 8 PNK/BLK V § z J I 150-.8 BLK ■ ■ 139-.8 PNK/BLK FUEL HEATER P 94 29 15 N 9 39 14 M 33 12 J L 93 11 18 120 24 30 420 I 9 Inr 19 || 508 50 35 97 150 1508-.8 YEL 1 WATER IN FUEL LAMP (SEE PAGE 105) I 3-3.0 PNK I FUEL SHUTOFF SOLENOID C199 12020274 (q\ ^ ENGINE GROUND G110 C100 12020183 DIESEL ENGINE FUEL CONTROLS A-87 6.2L V8 DIESEL ENGINE , HOT IN START OR RUN GAGE/IDLE 20 AMP I _______ COLD ADVANCE CONTROL FAST IDLE SOLENOID GENERATOR (SEE PAGE 12) COLD ADVANCE FAST IDLE TEMPERATURE SWITCH r (OPENS AS TEMPERATURE INCREASES) i . A n B z C198 2977373 C171 12004267 I 936-.8 LT GRN i 936-.0 LT GRN S109 I 39-.8 PNK/BLK I 39 r ) 5 0 8 ) ■ 39-.S PNK/BLK I I \ | [ WATER IN FUEL SENSOR m m 39-.8 p n k /b lk h f ^m m ^ m ^m m *m m ^m 39-.e p n k /b lk \ S202 (SEE PAGE 27) I i FUEL HEATER RWAL (SEE PAGE 116) □ 39-.8 PNK/BLK C196 12020397 39-.8 PNK/BLK ' m — W m m w ^ Q ) I 3-3.0 PNK I2 503 31] | 420 140 39 ■ | 508 440 8 i I3 I I2 25 | 439 97 93 | II 6 92 91 | 2 3 ■ GLOW PLUG CONTROLLER 50 I ENGINE GROUND G110 DM£ FUEL SHUTOFF SOLENOID 3-3.0 PNK 1 68 35 = U (t a 12020183 12020274 A-88 DIESEL ENGINE FUEL CONTROLS 6.2L HD V8 DIESEL ENGINE F jI Ui L 1 III C100 F\ * 94 n 29 * dl 15 I 9 39 14 p i 33 12 : 93 11 18 120 : 24 30 503 13931 140 L 440 68 i t 9 I 191 m 2 820 : WATER IN FUEL 508 25 3 50 r 93 35 2 97 439 91 92 6 ► I LAMP (SEE PAGE 105) IGNITION m • V 3 . 0 PNK S207 (SEE PAGE 13) ; SWITCH (SEE PAGE 13) COOLING FAN RUNS CONTINUOUSLY CIRCUIT OPERATION TEST Battery voltage is applied to the Auxiliary Cooling Fan Relay at all times by the RED (2) wire and by the PNK/BLK (39) wire through the GAGE/IDLE fuse, when the Ignition Switch is in RUN or START. When the Auxiliary Cooling Fan Temperature Switch closes at 107°C (225°F), the DK GRN (935) wire is grounded and the Auxiliary Cooling Fan Relay energizes. Battery voltage is applied across the Auxiliary Cooling Fan Motor and the Auxiliary Cooling Fan runs. DIAGNOSIS - AUXILIARY COOLING FAN COOLING FAN DOES NOT RUN TEST ACTION RESULT Disconnect auxiliary cooling fan temperature switch connector C170. Connect a fused jumper from DK GRN (535) wire at auxiliary cooling fan temperature switch connector C170 to ground. Auxiliary cooling fan does not run. GO to step 2. Auxiliary cooling fan runs. REPLACE auxiliary cooling fan temperature switch. Disconnect auxiliary cooling fan relay connector C190. Connect test lamp from PNK/BLK (39) wire at auxiliary cooling fan relay connector C190 to ground. Test lamp lights. GO to step 3. Test lamp does not light. CHECK condition of fuse (GAGE/IDLE) and/or LOCATE and REPAIR open in PNK/BLK (39) wire from auxiliary cooling fan relay to fuse block. Connect fused jumper from DK GRN (535) wire at auxiliary cooling fan temperature switch connector C170 to ground. Connect a test lamp from PNK/BLK (39) wire to DK GRN (935) wire at auxiliary cooling fan relay connector C190. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in DK GRN (535) wire. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire and fusible link. 5. Connect a 30 amp fused jumper from RED (2) wire to BLK/RED (702) wire at auxiliary cooling fan relay connector C190. Auxiliary cooling fan does not run. GO to step 6. Auxiliary cooling fan runs. REPLACE auxiliary cooling fan relay. 6. Leave 30 amp fused jumper connector. Disconnect auxiliary cooling fan connector C191. Connect a test lamp from BLK/RED (702) at auxiliary cooling fan connector C191 to ground. Test lamp lights. GO to step 7. Test lamp does not light. LOCATE and REPAIR open in BLK/RED (702) wires from auxiliary cooling fan to auxiliary cooling fan relay. 7. Connect a test lamp from BLK/RED (702) to BLK (151) wires at auxiliary cooling fan connector C191. Test lamp lights. REPLACE auxiliary cooling fan. Test lamp does not light. LOCATE and REPAIR open in BLK (151) wire from auxiliary cooling fan to ground terminal G106. 1. 2. 3. 4. Connect a test lamp from RED (2) wire at auxiliary cooling fan relay connector C190 to ground. RESULT ACTION 1. Place ignition switch in RUN position and with engine coolant temperature below 107°C (225°F), disconnect auxiliary cooling fan temperature switch connector C170. Auxiliary cooling fan runs. GO to step 2. Auxiliary cooling fan does no run. REPLACE auxiliary cooling fan temperature switch. I. Test lamp lights. CHECK for short in DK GRN (535) wire from fan relay to auxiliary cooling fan temperature switch. Test lamp does not light. REPLACE auxiliary cooling fan relay. Disconnect auxiliary cooling fan relay connector C190. Connect a test lamp from PNK/BLK (39) to DK GRN (535) wires at auxiliary cooling fan relay connector C190. AUXILIARY COOLING FAN A-89 7.4L V8 GASOLINE ENGINE .H O T IN S T A R T O R RUN GAGE/IDLE 20 AMP AUXILIARY COOLING FAN TEMPERATURE SWITCH (CLOSES WHEN COOLANT TEMPERATURE EXCEEDS 2 2 5 °F (107°C) I 2-.8 RST (FUSIBLE U NK)I S i S116 C193 1 a UJ CC BATTERY JUNCTION BLOCK I 2*2.0 RED I C192 12065171 935 S202 (SEE PAGE 27) 12065172 I 935-.8 DK GRN I AUXILIARY COOLING FAN RELAY m mmr l l 15 702-2.0 b lk / r e d v s o -.e p n k /b lk ' jm I r mmw jm m ^ ss-.sp n k/b lk ___ — r 29 1 94 1 12 | 33 | 11 ] 93 | \ C190 12065169 IP P— jl 14^ 39 1 9 1 C102 12020100 \ L ' I i z £ L l/P GO (5 0/1 30 ) £ % |4 2 0 440 f 2 439 8 0 6 / 39 L L AUXILIARY COOLING FAN jtm m im m r a 702 702-2.0 -2.0 b BLK/RED lk / r e d , 151-2.0 BLK I _93_ _M r S 111 | (SEE PAGE 16) TT 19 35 2 97 422 91 92 6 V 151-3.0 BLK SHEET METAL GROUND G106 A-90 AUXILIARY COOLING FAN 7.4L V8 GASOLINE ENGINE C100 12020184 FRAME GROUND G107 3 436 93 r 18 0 4 m jm m 120 : DIAGNOSIS - AIR CONDITIONING CIRCUIT OPERATION BLOWER CONTROLS COMPRESSOR CONTROLS Battery voltage is applied at all times to the HI Blower Relay, through the RED (2) wire. When the Blower Switch is in the OFF, LO or MED positions, the HI Blower Relay is de-energized. The Compressor for the A/C System is driven by the engine by means of a belt drive and the A/C Compressor Clutch. The Clutch allows the Compressor to be disengaged when the A/C is not required. With the Ignition Switch is in the RUN and ACC position, voltage is supplied to the Selector Control by way of the BRN (50) wire through the HTR A/C Fuse. This voltage is supplied, through the Selector Control, and then through the BRN/WHT (64) wire to the Blower Switch and Resistor Block. At the Resistor Block, voltage is dropped through three resistors. This reduced voltage flows through the DK BLU (101) wire to the de-energized, HI blower relay. Since the Hi blower relay is de­ energized, circuits 101 and 65 are connected through the relay. This reduced voltage flows through the PPL (65) wire to the Blower Motor and the Blower Motor will run at a slow speed. Operation of the Compressor depends on the particular A/C Mode selected at the Heater and A/C Controller. With A/C ON selected, battery voltage flows through the Selector Control to the Evaporator Pressure Control Switch by way of the LT GRN (66) wire. Voltage flows through the normally closed contacts of the Evaporator Pressure Control Switch to the A/C Compressor Clutch. The coil is energized and the A/C Compressor Clutch engages. When the Blower Switch is turned to LO, voltage flows through the Blower Switch, to the Resistor Block, through the TAN (63) wire. Voltage flows through two resistors, through the DK BLU (101) wire, through the contacts of the de-energized HI Blower Relay to the Blower Motor by way of the PPL (65) wire. When the Blower Switch is turned to MED, voltage flows through the Blower Switch, to the Resistor Block, through the LT BLU (72) wire. Voltage flows through one resistor, through the DK BLU (101) wire, through the contacts of the de-energized HI Blower Relay to the Blower Motor by way of the PPL (65) wire. When the Blower is turn to HI, voltage flows through the Blower Switch, to the HI Blower Relay, through the ORN (52) wire. This voltage flows through the coil of the HI Blower Relay. With the HI Blower Relay energized, battery voltage flows through the RED (2) wire, through the contacts of the energized HI Blower Relay to the Blower Motor by way of the PPL (65) wire. This allows battery voltage to power the Blower Motor. If the refrigerant pressure drops to a point which may cause icing of the evaporator, the Evaporator Pressure Control Switch opens, de-energizing the A/C Compressor Clutch. When the refrigerant pressure rises to a point where cooling is required again, the Evaporator Pressure Control Switch closes to re-energize the A/C Compressor Clutch. The A/C Compressor Clutch Diode is connected across the terminals of the A/C Compressor Clutch. Whenever the clutch is de-energized, the magnetic field around it collapses, generating an induced voltage in the clutch coil. The Diode provides a path for the current resulting from the induced voltage so that other circuit components are not damaged by it. PRELIMINARY CHECKS: Outside temperature must be above 16°C (60°F) in order to properly diagnose system. A /C C O M P R E S SO R C LU TC H DO ES N O T ENGAGE TEST 1. 2. 3. 4. RESULT ACTION Place ignition switch in RUN, selector control in MAX. Connect voltmeter from BRN (50) wire at selector control connector C233 to ground. Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in BRN (50) wire from selector control to fuse block. CHECK HTR/AC fuse. Disconnect A/C compressor control switch connector C178 and place selector control to MAX. Connect a fused jumper between LT GRN (66) wire and DK GRN (59) wire at A/C compressor control switch connector C178. A/C clutch engages. GO to step 4. A/C clutch does not engage. CHECK for open A/C compressor control switch. If A/C compressor control switch is open and refrigerant pressure is normal, REPLACE A/C compressor control switch. Connect voltmeter from DK GRN (59) wire at compressor clutch connector C165 to ground. Battery voltage. GO to step 5. No voltage. LOCATE and REPAIR open in DK GRN (59) wire from A/C compressor clutch to A/C compressor control switch. Connect voltmeter from DK GRN (59) wire to BLK (150) wire at A/C compressor clutch connector C165. Battery voltage. REPLACE A/C compressor clutch. No voltage. LOCATE and REPAIR open in BLK (150) wire from A/C compressor clutch to ground terminal G110. REAR BLOWER CONTROL Battery voltage is supplied to the Blower Switch through the AUX HTR A/C Fuse and the BRN (50) wire. When the Blower Switch is turned to LO, voltage flows through the Blower Switch to the Resistors by way of the YEL (51) wire. Voltage flows through two resistors, through the ORN (52) wire to the Rear Blower Motor. When the Blower Switch is turned to HI, voltage flows through the Blower Switch directly to the Rear Blower Motor through the ORN (52) wire. AIR CONDITIONING A-91 BLOWER MOTOR DOES NOT OPERATE IN ANY MODE ACTION RESULT TEST BLOWER MOTOR DOES NOT OPERATE IN HI 1. Place ignition switch to RUN, selector control to VENT and blower switch to HI. Disconnect blower motor connector C180. Connect voltmeter from PPL (65) wire at blower connector C180 to ground terminal G117. Battery voltage. REPLACE blower motor. No voltage. GO to step 2. 2. Connect voltmeter from BRN (50) wire at selector control connector C233 to ground. Battery voltage. GO to step 3. No voltage. CHECK condition of HTB/AC fuse. If fuse is good, LOCATE and REPAIR open in BRN (50) wire from selector control connector C233 to fuse block. 3. 4. 5. Connect voltmeter from BRN/WHT (64) wire at blower switch connector C234 to ground. Connect voltmeter from ORN (52) wire at HI blower relay connector C177 to ground. Disconnect HI blower relay connector C177. Connect voltmeter from ORN (52) wire at HI blower relay connector C177 to BLK (150) wire. 6. Connect HI blower relay connector C177. Connect voltmeter from PPL (65) wire at HI blower relay connector to ground. 1. 2. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in BRN/WHT (64) wire between blower switch connector C234 and selector switch connector C233. If no open is found, REPLACE selector control. Battery voltage. GO to step 5. No voltage. LOCATE and REPAIR open in ORN (52) wire between HI blower relay connector C177 and blower switch connector C234. If no open is found, REPLACE blower switch. Battery voltage. GO to step 6. No voltage. LOCATE and REPAIR open in BLK (150) wire between HI blower relay connector C177 and ground terminal G115. Battery voltage. No voltage. A-92 AIR CONDITIONING TEST LOCATE and REPAIR open in PPL (65) wire between HI blower relay connector C177 and blower motor connector C180. REPLACE HI blower relay. 3. RESULT Place ignition switch to RUN, selector control to VENT and blower switch to HI. Connect voltmeter from ORN (52) wire at HI blower relay connector C177 to ground. Connect voltmeter to RED (2) wire at HI blower relay connector C177 to ground. Connect voltmeter to RED (2) wire at HI blower relay connector C177 to BLK (150) wire. ACTION Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in ORN (52) wire from HI blower relay to blower switch. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in RED (2) wire or fusible link. Battery voltage. REPLACE HI blower relay. No voltage. LOCATE and REPAIR open in BLK (150) wire to ground G115. BLOWER MOTOR DOES NOT OPERATE IN MED TEST 1. 2. RESULT ACTION Place blower switch to MED. Connect voltmeter to LT BLU (72) wire at blower switch connector C234 to ground. Battery voltage. GO to step 2. No voltage. REPLACE blower switch. Connect voltmeter to LT BLU (72) wire at blower resistor connector C179 to ground. Battery voltage. REPLACE blower resistor. No voltage. LOCATE and REPAIR open in LT BLU (72) wire between blower resistor and blower switch. BLOWER MOTOR DOES NOT OPERATE IN LO RESULT TEST 1. 2. ACTION Place blower switch to LO. Connect voltmeter to TAN (63) wire at blower switch connector C234 to ground. Battery voltage. GO to step 2. No voltage. REPLACE blower switch. Connect voltmeter to TAN (63) wire at blower resistor connector C179 to ground. Battery voltage. REPLACE blower resistor. No voltage. LOCATE and REPAIR open in TAN (63) wire between blower resistor and blower switch. DIAGNOSIS CHART - AIR CONDITIONING, REAR BLOWER MOTOR DOES NOT OPERATE IN LO BUT ONLY IN HI PRELIMINARY CHECKS: TEST CHECK condition of AUX HTR A/C fuse. If fuse is blown, LOCATE and REPAIR source of overload, then REPLACE fuse. If fuse is in good condition, use following diagnostic procedures. 1. BLOWER MOTOR DOES NOT OPERATE AT ALL TEST 1. 2. 3. 4. ACTION RESULT Disconnect blower motor connector C410. Place ignition switch in RUN position. Connect a test lamp from PPL (52) wire at blower motor connector C410 to ground. Test lamp lights. GO to step 2. Test lamp does not light. GO to step 3. Connect a test lamp from PPL (52) wire to BLK (2) wire at blower motor connector C410. Test lamp lights. REPLACE blower motor. Test lamp does not light. LOCATE and REPAIR open in ground BLK (2) wire between blower motor and ground terminal G411. Connect a test lamp from BRN (50) wire at blower switch connector C281 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BRN (50) wire between blower switch connector C281 and fuse block connector C283. If no open is found, CHECK AUX HTR A/C fuse. Place blower switch in LO or HI. Connect a test lamp from blower switch connector C281 at wire that applies to position of switch to ground. LO is YEL (51) wire and HI is ORN (52) wire. Test lamp does not light. REPLACE blower switch. Test lamp lights. LOCATE and REPAIR open in wires to blower motor. 2. 3. Place blower switch in LO position. Connect a test lamp from YEL (51) LO wire at blower motor switch connector C281 to ground. RESULT ACTION Test lamp lights. GO to step 2. Test lamp does not light. REPLACE blower switch. Connect a test lamp from YEL (51) LO wire at blower resistor connector C181 to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in YEL (51) wire from blower resistor to blower switch. Connect a test lamp from ORN (52) wire at blower resistor connector C181 to ground. Test lamp lights. LOCATE and REPAIR open in ORN (52) wire between blower resistor connector C181 and splice S220. If no open is found, REPLACE resistor. BLOWER MOTOR DOES NOT OPERATE IN HI BUT ONLY IN LO TEST 1. Connect a test lamp from ORN (52) wire at blower switch connector C281 to ground. RESULT ACTION Test lamp lights. LOCATE and REPAIR open in ORN (52) wire between blower switch connector C281 and splice S220. Test lamp does not light. REPLACE blower switch. AIR CONDITIONING A-93 50-5.0 BRN f OFF LO Q i O— | <> U) BLOWER SWITCH C183 El 2965010 r — O hi 52 OMEDO0FF C180 HEATER BLOWER SWITCH QLOT I ? 2977976 GT104 8811217 52-2.0 ORN ■ 51-2.0_YEL_|« | 51-2.0 YEL 52-2.0 ORN ■ 52-2.0 ORN 72-2.0 LT BLU 72-2.0 LT BLU 50-2.0 BRN C235 12015952 A-98 HEATER FRONT 12015987 si S3 53203 C311 51-2.0 YEL I GT402 6268585 12015956 952-2.0 DK GRN 1 1 (M l (A 0) C312 50-2.0 BRN« I 50-2.0 BRN I 50 | q>[ 1 50 L - ] — f 12004727 C425 2973781 BUS BAR GROUND G201 EC BLOWER MOTOR AUXILIARY HEATER A-99 DIAGNOSIS - INSTRUMENT PANEL: GAGES AND INDICATORS CIRCUIT OPERATION FUEL GAGE The pointer of the Fuel Gage is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the E-coil and the circuit divides at the opposite end of the coil. One path continues to ground through the F-coil. Another goes to ground through the variable resistor of the Fuel Gage Sender. directly and the other is grounded through the Temperature Sender. This has 55 ohms resistance at 128°C (260°F) (hot coolant) and its resistance becomes greater at low temperatures. It is approximately 1400 ohms at 38°C (100°F). This causes the current through the Sender and one coil to increase as the coolant temperature increases. This moves the pointer. PRELIMINARY CHECKS Check condition of GAGE/IDLE fuse. If fuse is blown, locate and repair source of overload, then replace fuse. If fuse is in good condition, use the following diagnostic procedures. FUEL G AG E IN D IC A TE S FU LL OR BEYOND AT A LL TIM E S When the tank is low, the resistance of the Sender is low. A large flow of current passes through the E-coil and the Fuel Gage Sender resistor. This moves the pointer toward E on the scale. When the tank is full, the Sender resistance is high. More current now flows through the F-coil, moving the pointer toward F on the scale. With two coils operating the pointer, the Gage is not affected by changes in the system’s battery voltage. OIL PRESSURE GAGE The engine oil pressure is displayed by the Oil Pressure Gage. The pointer of the Gage is moved by two coils, and its operation is similar to that of the Fuel Gage. The Oil Pressure Sender is connected to the junction of the two coils. It has low resistance when the oil pressure is low, and 90 ohms resistance when the oil pressure is high. This changing resistance changes the current flow through the coils. The magnetic fields of the coils move the pointer from low to high. TEMPERATURE GAGE The Temperature Gage is also operated by two coils. Battery voltage is applied to both coils. One is grounded A-100 INSTRUMENT PANEL GAGES AND INDICATORS TEST VOLTMETER The Voltmeter measures the electrical system’s voltage with the Ignition Switch in RUN or START. With the engine stopped, the Voltmeter indicates Battery condition. With the engine running, the Voltmeter indicates Charging System operation. 1. LOW COOLANT INDICATOR The Low Coolant Indicator comes on to warn the driver when a low level of coolant exists in the radiator. Battery voltage is applied to the Low Coolant Module. When a low coolant condition exists, a signal is sent to the Low Coolant Module from the Low Coolant Sensor. The Low Coolant Module will provide a ground to the Low Coolant Indicator. The Low Coolant Sensor is not a switch that opens and closes. It has a very high resistance to ground, more than 50,000 ohms, when the engine coolant level is low. This causes the Low Coolant Module to light the Low Coolant Indicator. With more of the Sensor covered by coolant, its resistance decreases. When the fluid level is good, the resistance will be less than 10,000 ohms. With the Sensor resistance between 10,000 and 50,000 ohms, the Sensor is partly covered and the fluid is not low enough to cause the warning to be displayed. RESULT Disconnect fuel sender connector C409 and place ignition switch to RUN. Connect a fused jumper from PNK (30) wire at fuel tank sender connector C409 to ground. ACTION Fuel gage indicates full. LOCATE and REPAIR a short in PNK (30) wire. If no short is found, REPLACE fuel gage. Fuel gage indicates empty. CHECK fuel gage ground. If ground is good, REPAIR/REPLACE fuel gage sender. FUEL GAGE INDICATES EMPTY WHEN THERE IS FUEL IN THE TANK TEST 1. RESULT Disconnect fuel tank sender connector C409 and place ignition switch to RUN. ACTION Fuel gage indicates full. CHECK fuse gage ground. If ground is good, REPAIR/REPLACE fuel gage sender. Fuel gage indicates empty. LOCATE and REPAIR a short in PNK (30) wire. If no short is found, REPLACE fuel gage. FU EL G AG E IS INACCURATE TEST 1. Disconnect fuel tank sender connector C409. Connect one RED lead of Tester J 33431-B to PNK (30) wire and other to ground. Set resistance dials to 0 ohms and then to 90 ohms. Fuel gage should indicate empty and then full. (Allow time for gage to reach full due to anti-slosh device.) RESULT ACTION Gage responds correctly. CHECK fuel tank ground wire for high resistance. If ground is good, REPAIR/REPLACE fuel gage sender. Gage does not respond correctly. CHECK for high resistance in PNK (30) wire. If wire is good, REPLACE fuel gage. TEMPERATURE GAGE INDICATES HOT WITH ENGINE COOLANT BELOW OPERATING TEMPERATURE AND IGNITION SWITCH IN RUN RESULT TEST Disconnect temperature sender connector C107 and place ignition switch to RUN. OIL PRESSURE GAGE INDICATES HIGH PRESSURE AT ALL TIMES Temperature gage indicates cold. REPLACE temperature sender. Temperature gage does not indicate cold. LOCATE and REPAIR a short in DK GRN (35) wire. If no short is found, PERFORM diagnostic procedures under symptom “Temperature Gage Is Not Accurate.” 1. ACTION RESULT TEST ACTION Disconnect oil pressure sender connector C115 (Gasoline) or C116 (Diesel) and place ignition switch to RUN. Connect a fused jumper from TAN (31) wire at oil pressure sender connector C115 (Gasoline) or C116 (Diesel) to ground. Oil pressure gage indicates low pressure. REPLACE oil pressure sender. Oil pressure gage indicates high pressure. LOCATE and REPAIR open in TAN (31) wire. If wire is good, REPLACE oil pressure gage. TEMPERATURE GAGE INDICATES COLD ALL THE TIME RESULT TEST 1. Disconnect temperature sender connector C107. Ground the DK GRN (35) wire at temperature sender connector C107. Temperature gage indicates hot. Temperature gage does not indicate hot. Disconnect temperature sender connector C107. Connect red lead from J 33431 -B tester to DK GRN (35) wire and other lead to ground. Adjust resistance dials to 1400 ohms and then to 55 ohms. Temperature gage should indicate cold then hot. RESULT TEST REPLACE temperature sender. LOCATE and REPAIR open in DK GRN (35) wire. If wire is good, REPLACE temperature gage. TEMPERATURE GAGE IS NOT ACCURATE TEST OIL PRESSURE GAGE IS NOT ACCURATE ACTION ACTION Gage indicates correctly. REPLACE temperature sender. Gage is not correct. LOCATE and REPAIR open in DK GRN (35) wire. If wire is good, REPLACE temperature gage. 1. Disconnect oil pressure sender connector C115 (Gasoline) or C116 (Diesel). Connect one RED lead of J33431-B tester to TAN (31) wire at oil pressure sender connector C115 (Gasoline) or C116 (Diesel) and other lead to ground. Set resistance dials to 0 ohms and then to 90 ohms. The oil pressure gage should indicate low pressure and then high pressure. OIL PRESSURE GAGE INDICATES LOW PRESSURE WHEN 0 L PRESSURE IS GOOD 1. Disconnect oil pressure sender connector C115 (Gasoline) or C116 (Diesel) and place ignition switch to RUN. ACTION Oil pressure gage indicates correctly. REPLACE oil pressure sender. Oil pressure gage does not indicate correctly. LOCATE and REPAIR open in TAN (31) wire. If wire is good, REPLACE oil pressure gage. VOLTMETER IS NOT ACCURATE TEST TEST RESULT RESULT ACTION Oil pressure gage indicates high pressure. REPLACE oil pressure sender. Oil pressure gage indicates no or low pressure. LOCATE and REPAIR short TAN (31) wire. If wire is good, REPLACE oil pressure gage. Place ignition switch to RUN position. Connect a voltmeter between positive and negative terminals of the battery. RESULT ACTION Voltage reading is same as vehicle’s voltmeter. Voltmeter is good. Voltage reading is different from vehicle’s voltmeter. LOCATE and REPAIR open in PNK/BLK (39) wire and BLK (150) wire at instrument cluster. If wires are good, REPLACE voltmeter. INSTRUMENT PANEL A-101 GAGES AND INDICATORS SPEEDOMETER IS INOPERATIVE OR INACCURATE RESULT TEST 1. 2. ACTION Disconnect instrument cluster connector C203 and place ignition switch to RUN. Connect voltmeter from LT BLU/BLK (824) wire at instrument cluster connector C203 to ground. Battery voltage. GO to step 2. No voltage. CHECK condition of HTR A/C fuse. If fuse is good, LOCATE and REPAIR open in LT BLU/BLK (824) wire. Connect voltmeter from LT BLU/BLK (824) wire to BLK (150) wire at instrument cluster connector C203. Battery voltage. REFER to speed sensor in Emissions Manual (Gasoline) or Service Manual (Diesel) for further diagnosing. No voltage. LOCATE and REPAIR open in BLK (150) wire from instrument cluster to ground. LOW COOLANT INDICATOR DOES NOT LIGHT WITH COOLANT LEVEL LOW (DIESEL ONLY) TEST 1 . Disconnect low coolant probe RESULT ACTION Low coolant indicator lights. REPLACE low coolant probe. Low coolant indicator does not light. GO to step 2. 2. Disconnect low coolant module connector C225. Connect voltmeter from PNK/BLK (39) wire at low coolant module connector C225 to ground. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in PNK/BLK (39) wire. 3. Connect voltmeter from PNK/BLK (39) wire to BLK (150) wire at low coolant module connector C225. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in BLK (150) wire. 4. Connect voltmeter from GRA (69) wire at low coolant module connector C225 to ground. Battery voltage. GO to step 5. No voltage. LOCATE and REPAIR open or short to ground in GRA (69) wire going from low coolant module to low coolant indicator lamp. 5. Connect voltmeter from PNK/BLK (39) wire to YEL/BLK (68) wire at low coolant module connector C225. Battery voltage. LOCATE and REPAIR short to ground in YEL/BLK (68) wire from low coolant module to low coolant probe. No voltage. REPLACE low coolant module. connector C186 and place ignition switch to RUN. Observe low coolant indicator light. LOW COOLANT INDICATOR IS LIT WHEN COOLANT LEVEL IS GOOD TEST Connect a fused jumper from low coolant probe connector C186 to ground. Place ignition switch to RUN and observe low coolant indicator light. RESULT Low coolant indicator goes out. REPLACE low coolant probe. Low coolant indicator stays lit. LOCATE and REPAIR open in YEL/BLK (68) wire. If wire is good, follow diagnostic procedures listed under symptom “ Low Coolant Indicator Does Not Light With Coolant Level Low.” A-102 INSTRUMENT PANEL GAGES AND INDICATORS ACTION ILLUM ILLUM ILLUM ILLUM ILLUM 0 <0 0 0 0 L05 - ENGINE, 5.7L (350 CIO) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (464 CIO) V8 GAS ENGINE, VIN N LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE FIBER OPTIC CABLE ASHTRAY ILLUMINATION CANADIAN DAYTIME RUNNING INSTRUMENT CLUSTER A-103 GLOW PLUG RELAY AND CONTROLLER (LL4, LH6) (SEE PAGE 04) LOW COOLANT SENSOR (LL4) (SEE PAGE 106) I 33-.5 TAN/WHT 4 A-104 INDICATOR LAMPS SUBURBAN/UTILITY 419-.0 BRN/WHTl I 33-. 5 TAN/WHT | A-106 INDICATOR LAMPS FLEETSIDE, WIDESIDE, CREW-BONUS CAB RPO CODES wvwwwwww/ L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (454 CID) V0 GAS ENGINE, VIN N LL4 - ENGINE, 6.2L (378 CID) V0 HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (378 CID) V0 DIESEL ENGINE, VIN C MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE MT1 - AUTO TRANS, HD 4-SPD., WfTH OVERDRIVE S HOT IN START OR RUN < Ivw w w W V W V ^ A GAGE/IDLE 20 AMP 12064770 135- 8 DKGRN COOLANT TEMPERATURE SENDER C107 12015306 120 31 FUEL PUMP OIL PRESSURE SWITCH t 31-.8 TAN 440 (L05, L19) 31-.5 TAN (LL4 WITH MT1) OIL PRESSURE SENDER C116 2977935 (LH6, LL4) FUEL TANK SENDER (LH6, LL4) I30-.BPNK BUS BAR GROUND G200 FRAME GROUND G409 A-108 INSTRUMENT PANEL GAGES SUBURBAN/UTILITY RPO CODES VAAMiWvM/WVW < L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (454 CIO) V8 GAS ENGINE, VIN N LL4 - ENGINE, 8.2L (378 CID) V8 HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C HOT IN START OR RUN ? W vw w vw w ^ GAGE/IDLE 20 AMP 39-.8 PNK/BLK T S202 (SEE PAGE 27) I 3 9-5 PNK/BLK V \ DRAC (SEE PAGE 75) 35-.8 DK GRN COOLANT TEMPERATURE SENDER C183 12052644 l/P CLUSTER CONNECTOR (SEE PAGE 103) 31-.5 T A N i 31-.8 TAN FUEL PUMP OIL PRESSURE SWITCH (L05, L19) 131-.8 TAN ■ ■ ■■■ 31-.5 TAN (LL4 WITH MT1) OIL PRESSURE SENDER S201 (SEE PAGES 17, 19) C185 2977935 (LH6, LL4) ■35-5 DK GRN1 ECM/PCM (SEE PAGE 60) C 30 ) 20-1.0 TAN/WHT1 • 120-1.0 TAN/WHT S139 (SEE PAGE i ELECTRIC FUEL PUMP FUEL GAGE SENDING UNIT (L05, L19) FUEL TANK SENDER (LH6, LL4) 30-.8 PNK I 130-.8 PNK I m tm t 30-.8 PNK ■ ■ w M I 30-.5 PNK FRAME GROUND ( Q G409 -= r BUS BAR GROUND G200 INSTRUMENT PANEL GAGES A-109 FLEETSIDE INSTR LPS 5 AMP HEATER A/C CONTROL ASSEMBLY LAMP * l/P CLUSTER CONNECTOR RADIO (SEE PAGES 144, 145) C203 12026261 GROUND G200 A-110 INSTRUMENT PANEL LAMPS T H E S A F E T Y BELT W A R N IN G B U ZZER DO ES N O T O P ER A TE CIRCUIT OPERATION TEST SAFETY BELT WARNING BUZZER 1. With the Ignition Switch in RUN or START, voltage is applied through the GAGE/IDLE Fuse to the Audio Alarm at the Convenience Center. With the driver’s safety belt not buckled, terminal 39 of the Audio Alarm is grounded through the Safety Belt Switch. The Fasten Belts Indicators always goes on for about five seconds when the Ignition Switch is turned to RUN or START. IGNITION KEY WARNING BUZZER Whenever the key is in the ignition switch, the ignition switch is in LOCK, OFF, or ACC and the driver’s door is open, terminal 80 or the audio alarm is grounded. This sounds the buzzer. LAM PS-ON WARNING BUZZER panel dimmer switch is not in the dimmest setting, voltage is applied through the INSTR LPS fuse to the audio alarm module through the GRA (8) wire. With the panel dimmer switch at its dimmest setting the voltage may not be enough to activate the alarm. When the ignition switch is in RUN or START, voltage is applied through the GAGE/IDLE fuse and the PNK/BLK (39) wire. These two voltage are sensed and the alarm is not sounded. The alarm is activated when the ignition switch is turned to LOCK, OFF, or ACC, the GAGE/IDLE fuse loses voltage. The audio alarm module senses this loss of voltage and activates the alarm. If voltage is still available from the INSTR LPS fuse. Voltage from the STOP HAZ fuse is applied to sound the alarm. The alarm can be turned off by turning off the light switch. When the light switch is in HEAD or PARK and the 2. GO to step 2. Test lamp does not light. CHECK STOP/HAZ fuse. If fuse is good, REPAIR open in ORN (140) wire. Install audio alarm module. 2. Connect a self-powered test lamp form LT GRN (80) at convenience center to ground. Test lamp lights. REPLACE audio alarm module. Test lamp does not light. GO to step 3. Connect a self-powered test lamp from LT GRN (80) wire at turn signal switch connector C205 to ground. Test lamp lights. LOCATE and REPAIR open in LT GRN (80) wire from turn signal switch connector C205 to convenience center. Install audio alarm module. Connect a self-powered test lamp from TAN (159) wire at turn signal switch connector C205 to ground. 5. Connect a self-powered test lamp from TAN (159) wire at LH jamb switch connector C208 to ground. Test lamp does not light. CHECK condition of the GAGE/IDLE fuse. If fuse is not blown, LOCATE and REPAIR open in PNK/BLK (39) wire from convenience center to fuse block. Connect test lamp from WHT (238) wire and BLK (150) wire at convenience center. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from convenience center to bus bar ground. Test lamplights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in WHT (238) wire from safety belt retractor switch to convenience center. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire from safety belt retractor switch to bus bar ground. Test lamp does not light. REPLACE safety belt retractor switch. TEST ACTION Test lamp lights. 4. GO to step 2. TH E S A F E T Y B E LT W A R N IN G B UZZER O P E R A TE S W H EN S A FE T Y BELT IS BUC KLED 1. Turn ignition switch OFF. Leave key in ignition switch. Open left door. Remove audio alarm module. Connect a voltmeter from ORN (140) wire at convenience center to ground. 3. Test lamplights. 4. Buckle safety belt. Connect test lamp from BLK (150) wire at safety belt retractor switch connector C306 to ground. KEY-IN WARNING ALARM DOES NOT OPE RATE RESULT ACTION Connect test lamp from PNK/BLK (39) wire at convenience center to ground. 3. Connect test lamp from WHT (238) wire at safety belt retractor switch connector C306 to ground. DIAGNOSIS -- AUDIO ALARMS TEST RESULT Test lamp does not light. GO to step 4. Test lamp lights. REPLACE turn signal switch, INSTALL audio alarm module. Test does not light GO to step 5. Test lamp lights. LOCATE and REPAIR open in TAN (159) wire between LH door jamb switch connector C208 and turn signal switch connector C205. INSTALL audio alarm module. Test lamp does not light. REPLACE LH door jamb switch. INSTALL audio alarm module. RESULT Disconnect safety belt retractor switch connector C306. ACTION Safety belt buzzer stops. REPLACE safety belt retractor switch. Safety belt buzzer continues. CHECK for a short from WHT (238) wire to ground. REPAIR as required. LAMPS-0 J WARNING ALARM DOES NOT OPERATE TEST 1. 2. 3. RESULT ACTION Remove audio alarm module. Turn ignition switch to RUN. Turn lamps switch ON. Connect voltmeter from PNK/BLK (39) wire at convenience center to ground. Battery voltage. GO to step 2. No voltage. CHECK GAGE/IDLE fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (29) wire. Connect voltmeter from GRA (8) wire at convenience center to ground. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in GRA (8) wire. Connect ohmmeter from BLK (150) wire at convenience center to ground. Low resistance. REPLACE audio alarm module. High resistance. LOCATE and REPAIR cause of high resistance in BLK (150) wire. AUDIO ALARM A-111 RPO COOES LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C L05 - ENGINE, 5.7L (454 CID) V8 GAS ENGINE, VIN K MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE CONVENIENCE CENTER GAGE/IDLE 20 AMP SAFETY BELT RETRACTOR SWITCH (OPEN WHEN SEAT BELT ENGAGED) 150 T“ 8911773 i/p U39-,8 PNK/BLK I 39-.8 PNK/BLK I ^ CLUSTER CONNECTOR (SEE PAGE 105) r 39-.8 PNK/BLK I 39-.8 PNK/BLK | ^ ■ r S202 39-.8 PNK/BLK ■ '/fils WATER IN FUEL FILTER LAMP .. (SEE PAGE 105) (RPO LH6, LL4) LOW COOLANT WARNING MODULE 39-.8 PNK/BLK } 39-.8 PNK/BLK I I 39- 8 PNK/BLK | J If 39*.8 PNK/BLK I (SEE PAGE 104) L 39-.8 PNK/BLK I BUS BAR GROUND G200 A-112 SAFETY BELT WARNING BUZZER |5 co o £ i JJ T 238 t 5 5 CD ] C306 8911772 RPO CODES yvw w w w w f S m vw w w w m TVWWWVWV'A INSTR LPS 5 AMP STOP HA2 15 AMP LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J MD8 - AUTO TRANS, 4-SPD., WITH OVERDRIVE S HOT IN START OH RUN ^ HOT AT ALL TIMES < GAGE/IDLE 20 AMP [ HORN/DM 20 AMP a 240-1.0 ORN L 140-.8 ORN I HORN RELAY S210 140-.8 ORN I CONVENIENCE CENTER SAFETY BELT SW -2 3 8 GROUND -150 FASTEN BELTS -2 3 7 IGNITION - 39 IGN KEY SW -8 0 BATTERY -1 4 0 LIGHTS ON SW o L I 140-.8 ORN I 80-.5 LT GRN I m 8 140 80 238 150 237 14O-.0 ORN I RWAL MODULE (SEE PAGE 116) I 39-.8 PNK/BLK I 39 S202 (SEE PAGE 27) - 8 -2 7 -1 4 0 r a HAZARD FLASH ° o 2 HZ/F HORN RELAY AUDIO ALARM % FRONT <3 in cb l i “ —I z cc O r 3 CD l/P CLUSTER CONNECTOR (SEE PAGE 105) 237-.8 Y E L I 240-1.0 ORN I I 8-.5 GRA I S201 (SEE PAGES 17, 19) S209 y -f 17 19 16 ------- .8 YEL ------- .8 PPL - 27 ------- .8 BRN - 15 — .8 DK BLU 18 RADIO (SEE PAGES 144, 145) 3 cn o S I S-.5 GRA I -------.8 WHT ---- 8 DKGRN -.8LTBLU l/P CLUSTER CONNECTOR (SEE PAGE 105) HEATER, A/C CONTROL ASSEMBLY LAMPS (SEE PAGE 110) 28 l 8 .5 GRA i r 159 159-.8 TAN 8-.5 GRA I BUS BAR GROUND G200 0 LH DOOR JAMB SWITCH (SEE PAGE 118 TURN SIGNAL SWITCH a KEY-IN AND LIGHTS-ON WARNING BUZZER A-113 CIRCUIT OPERATION BRAKE INDICATOR DOES NOT LIGHT DURING A WARNING CONDITION OR DURING THE ANTILOCK SYSTEM CHECK Battery voltage is applied to the Brake Indicator when the Ignition Switch is in RUN or START. Two switches are connected to the Brake Indicator. When either of these two switches close, ground is provided and the indicator lights. The Brake Indicator is also connected to the Electronic Rear Wheel Brake Control Module. Indicator when there is low brake fluid pressure in one of the two hydraulic brake systems. This could be caused by a leak in one of the brake lines. Refer to Section 5 in the 1991 R/V,P Light Truck Service Manual for Switch reset procedures. This can only be accomplished after the faulty system has been repaired. 1. The Park Brake Warning Switch provides a ground when the Parking Brake is applied. The Park Brake Indicator lights to alert the driver. The Electronic Rear Wheel Brake Control Module grounds the Brake Indicator when the module senses a fault in the Antilock Brake System. For Electronic Rear Wheel Brake Control Diagnosis, refer to Section 5A in the 1991 R/V,P Light Truck Service Manual. 2. The Brake Pressure Switch closes to light the Brake TEST DIAGNOSIS - BRAKE SYSTEMS BRAKE INDICATOR REMAINS ON WITH IGNITION SWITCH IN RUN AND PARK BRAKE OFF RESULT TEST 1. 2. Disconnect park brake switch connector C293. Disconnect brake pressure warning switch connector C104. ACTION Brake indictor lamp does not go out. GO to step 2. Brake indicator lamp goes out. CHECK adjustment of park brake switch. If adjustment cannot be corrected, REPLACE brake switch. Brake indicator lamp does not go out. GO to step 3 if not equipped with Electronic Rear Wheel Brake Control. GO to step 4 is equipped with Electronic Rear Wheel Brake Control. Brake indictor lamp goes out. 3. 4. CHECK for a possible leak or loss of fluid in the brake system. Connect a self-powered test lamp from TAN/WHT (33) wire at park brake warning switch C293 to ground. Test lamp lights. LOCATE and REPAIR short in TAN/WHT (33) wire. Test lamp does not light. CHECK instrument cluster and indicator lamp. Disconnect Electronic Rear Wheel Brake Control module connector C103. Brake indicator lamp does not go out. CHECK wiring between instrument cluster and each switch and module for a short to ground. If wiring is good, the problem is in the instrument cluster. Brake indicator lamp goes out. CHECK for an inoperative antilock brake system. Refer to Section 5A of the 1991 R/V, P Light Truck Service Manual for a diagnostic circuit check. A-114 BRAKE WARNING SYSTEM 3. RESULT ACTION Disconnect park brake switch connector C293. Connect a fused jumper from park brake switch connector C293 to ground. Brake indicator lamp does light. Disconnect brake pressure warning switch connector C104. Connect a fused jumper from TAN/WHT (33) wire at brake pressure warning switch connector C 104 to ground. Brake indicator lamp does not light. GO to step 3. Brake indicator lamp lights. REPLACE brake pressure warning switch. Disconnect electronic rear wheel brake control module connector C103. Connect a fused jumper from TAN/WHT (33) wire at antilock module connector C103 to ground. Brake indicator lamp does not light. CHECK wiring and in-line diode (if equipped) between instrument cluster and each switch and module for an open. If wiring is good, the problem is in the instrument cluster. Brake indicator lamp lights. CHECK for an inoperative antilock brake system. Refer to Section 5A of the 1991 R/V, P Light Truck Service Manual for a diagnostic circuit check. Brake indicator lamp lights. GO to step 2. CHECK adjustment of park brake switch. If adjustment cannot be corrected, REPLACE brake switch. [ 300 } A [ BL_g_J f j [~36l p c 133-. 5 TAN/WHT | oldD 33-.5 TAN/WHT | C210 6294641 IGNITION SWITCH S219 l\ l/P Z < ID I1— ± L —i .m 115 !291941 1141391 9 I \ l l r t 2 l3 3 | 111 193 il II I3 3 -.5 TAN/WHT I : 94 29 9 39 33 12 93 11 18 : 24 15 14 J 120 9 30 19 420 440 2 439 806 39 L 140 120 31 3 50 436 r 35 2 93 97 422 91 92 6 : C102 12020100 I 33-.S TAN/WHT I PARK BRAKE WARNING SWITCH BRAKE SET C° BRAKE PRESSURE WARNING = SWITCH (CLOSED WITH PARK BRAKE APPLIED) I 33-.5 TAN/WHT I C293 12004267 BRAKE WARNING SYSTEM A-115 WITH RWAL VsMMA/WV/WW yw vw w w w w S HOT AT ALL TIMES < > HOT IN ACCY OR RUN < >VVV\VVVVVW'i ^W vvw vw w w vA ECM 1 10 AMP RWAL CONTROLLER ANTILOCK BRAKE VALVE (Q ) A-116 REAR WHEEL ANTILOCK BRAKES ENGINE GROUND G110 CIRCUIT OPERATION DOME LAMP DOES NOT WORK OR STAYS ON ALL THE TIME TEST COURTESY DOME, COMPARTMENT BOX, UNDERHOOD LAMPS CARGO LAMP VANITY, l/P CARGO AND Voltage is applied at all times from the T/L CTSY Fuse to the Courtesy Lamp, Dome Lamp, l/P Compartment Box Lamp and Vanity Lamps. The Courtesy and Dome Lamps turn on when a ground path is provided by the Panel Dimmer Switch or one of the Door Jamb Switches. The l/P Compartment Box and Vanity Lamps have their own switches that provide ground paths when their switches close. 1. Voltage is applied at all times through the HORN/DM Fuse to the Cargo Lamp Switch. When the Cargo Lamp Switch is turned on, voltage flows through the switch to the Lamp. On models with a tailgate, a ground path is provided when the tailgate is opened. 2. UNDERHOOD LAMP Voltage is applied at all times to the Underhood Lamp from the Junction Block, through an in-line fuse. When the switch is closed a ground path is provided. 3. DIAGNOSIS - INTERIOR LAMPS PRELIMINARY CHECKS: Checks condition of T/L CTSY fuse. If fuse is good, refer to appropriate diagnostic procedure. TEST 1. 2. c o u RTESY LA M P S D O N O T OPERA1rE RESULT 4. ACTION Connect test lamp from ORN (40) wire at courtesy lamp connector C218 to ground. Check at each courtesy lamp. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire. Open right door. Connect test lamp from ORN (40) wire to WHT (156) wire at courtesy lamp connector C218. Test lamp lights. REPLACE bulb. Test lamp does not light. CHECK to make sure jamb switch is closing. If switch closes, LOCATE and REPAIR open in WHT (156) wire and BLK (150) wire. CARGO LAMP DOES NOT WORK TEST RESULT ACTION 1. Turn cargo switch on. Connect a test lamp from ORN (140) wire at cargo lamp connector C436 to ground. Test lamp lights. GO to step 2. Test lamp does not light. GO to step 3. 2. Test lamp lights. REPLACE bulb. Test lamp does not light. LOCATE and REPAIR open in WHT (156) wire from cargo lamp to light switch. Connect a test lamp from ORN (140) wire to WHT (156) wire at cargo lamp connector C436. 3. Connect a test lamp from ORN (40) wire at cargo lamp switch connector C431 to ground. 4. Connect a test lamp from ORN (140) wire at cargo lamp switch connector C430 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire. Test lamp lights. LOCATE and REPAIR open in ORN/WHT (140) wire from cargo lamp switch to cargo lamp. Test lamp does not light. REPLACE cargo lamp switch. A-118 DOME LAMPS, l/P COMPARTMENT LAMP, CARGO LAMP, UNDER­ HOOD LAMP AND LIGHTED VANITY MIRROR RESULT ACTION Connect a test lamp from ORN (40) wire at both dome lamps to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire. Open both doors and turn panel lamp switch to ON. Connect a test lamp from ORN (40) wire to WHT (156) wire at dome lamp. Test lamp lights. REPLACE bulb if dome lamp did not work. If dome lamp stayed ON all the time, GO to step 3. Test lamp does not light GO to step 3. Disconnect jamb switch connectors. Connect an ohmmeter from WHT (156) terminal to BLK (150) terminal at jamb switch. Take a reading with door open and a reading with door closed. With door open reading must be 0 ohms and door closed, infinite ohms. Correct readings. GO to step 4. Incorrect readings. REPLACE jamb switch(es) that have incorrect reading. Disconnect light switch connector C202. Connect an ohmmeter from WHT (156) terminal to BLK (150) terminal at light switch. Turn light switch to ON and the OFF and take a reading in each position. When ON, reading must be 0 ohms and when OFF, reading must be infinite ohms. Correct readings. LOCATE and REPAIR open or short in WHT (156) wire and BLK (150) wire. Incorrect readings. REPLACE light switch. l/P COMPARTMENT BOX LAMP DOES NOT WORK RESULT TEST ACTION 1. Open l/P compartment box door. Connect test lamp from ORN (40) wire l/P compartment box lamp connector C230 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in ORN (40) wire. 2. Connect test lamp from ORN (40) wire to BLK (150) wire at l/P compartment box lamp connector C230. Test lamp lights. REPLACE l/P compartment box lamp assembly. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from l/P compartment box lamp to ground terminal G202. UNDERHOOD LAMP DOES NOT WORK TEST RESULT ACTION 1. Connect a test lamp from ORN (40) wire to BLK (150) wire at underhood lamp connector C101 A. Test lamp lights. REPLACE underhood lamp bulb. Test lamp does not light. GO to step 2. 2. Connect test lamp to RED (2) wire at in-line fuse connector C100A to ground. Test lamp lights. REPLACE in-line fuse. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire or fusible link. C219 12004886 RH DOOR JAMB SWITCH § (CLOSED WITH DOOR OPEN) IREAR |C] |C] 0 ^BATJ ig m E 0 ] S HOT AT ALL TIMES C 1 c° 1 I I i n M A m [] i WOO i RH REAR DOORJAMB jcuj8® *N 1™ n w/-\!Vfw dqqp OPE ) SWITCH 8911287 yvw w w vw / @] 0 [w] g] [d] i ] H] I GT602 i (i i [i (SUBURBAN ONLY) 156 (i i C438 6288872 ACC LPS SHUNT I . I h J h SHUNT _ _ _ ^ s jp g p i p i INSTR LPS 153 B d HORN/DM 1GN lS K | AUX HTR A/C j p H & G GAGE/IDLE HTR A/C 30 A TURNB/U PWRWDO DS Gd Q DRL FRONT W E FRONT DOME LAMP REAR DOME LAMP (SUBURBAN/UTILITY) (SUBURBAN/UTILITY) t 0 frfl EkB 0 D S 0 0 CRANK__________ i IT fl-A p ' — [fc-H W E D d ECM 1 Ip w l/P COMPARTMENT BOX LAMP AND SWITCH o S ^ Q Q Q Q S lri ) □ O S ^ J i FUSE BLOCK 12103404 C218 I156-.8W HT I 156-.8 WHT I40-.8 ORN ■ ■ ■ • p 94 29 15 N 9 39 14 M 33 12 L 93 11 18 120 J 9 420 440 439 806 L 140 3»r1 S413 2 39 : 120 31 3 50 436 35 2 93 97 422 91 92 6 S412 r GENERATOR AND BATTERY (SEE PAGE 10) 156-.8 W H T I REAR PANEL DOOR/END GATE HARNESS EXTENSION (SUBURBAN ONLY) (SEE PAGE) 44 40-.8 ORN C323 12047682 i 12047683 LIGHTED VANITY MIRROR ■ 159-.8 TAN I 150DOME 2 - GT502 CARGO LAMPS (SUBURBAN ONLY) (SEE PAGE 120) 12015958 CIRCUIT BREAKER 25 AMP »PARK 156-.8 WHT LH DOOR JAMB SWITCH HEAD OFF (CLOSED WITH DOOR OPEN) 'PARK t LIGHT SWITCH SHEET METAL GROUND / q ) G200 ^ KEY-IN WARNING BUZZER (SEEPAGE 113) C208 12047682 12047683 C437 6288872 LEFT REAR (CLOSED WITH DOORJAMB DOOROPEN> SWITCH DOME LAMPS, l/P COMPARTMENT LAMP, AND LIGHTED VANITY MIRROR A-119 RPO CODES E63 - FLEETSIDE BODY JPCAO HTR fc] (c] S i m ® ^B A T J m 0 0 ® [U 0 [U 1 ® 11 WDO m 0 M GNJ m " m Tf VTTTi yvvw w vw vw > HOT AT ALL TIMES ? Ta w 11111 ii A11111 w w smv^ * ° I) (1 1 ID II (1 I o< ACC LPS PWR | r 4 1 v ^ Dd K l D d K l T/L CTSY GAGE/IDLE HTR A/C n — n I 30 A L^U ECM B TURN B/U PWR WDO D 3 nun DRADIO d I kS [ k&h DWIPER 3 I !*fi I k f i EJ D3 ECM 1 ^ Ik s IpS p i X H T R A /C STOP HA2 CD DRL D3 □ D 0 CRANK I kS CARGO LAMP SWITCH FLEETSIDE MODELS (E63) C431 2962793 \ HORN/DM 20 AMP I kH S'S S'S o) { □ □ B^B I FRONT CARGO LAMP FUSE BLOCK 12103404 FLEETSIDE MODELS (£63) COURTESY LAMP AND FRONT DOOR JAMB SWITCHES (SEE PAGE 119) I 40-.8 ORN C219 12004886 C433 12015987 C455 2977253 JI156-.8 WHT w 156*.8 WHT 40-.8 ORN I C442 12015952 REAR GATE SWITCH ^ jh 5 6 ^ J C456 12004333 6288544 (UTILITY ONLY) I DOME . LAMPS (SEE PAGE 112) A-120 CARGO LAMP BATTERY JUNCTION BLOCK C100A 12033769 S142 z (L o UNDERHOOD LAMP SHEET METAL GROUND ■=■ G118 S UNDERHOOD LAMP A-121 CRUISE CONTROL DOES NOT OPERATE CIRCUIT OPERATION The Cruise Control System operates a mechanical linkage to the throttle by means of a Vacuum Motor. This is a diaphragm moved by a vacuum applied to one side. A solenoid operated valve connects the Vacuum Motor to a Vacuum Tank. Another solenoid valve vents the vacuum to reduce the suction. The Cruise Control Module controls the vacuum motor and the throttle by pulsing these solenoid valves on and off. One input to the module is the vehicle speed. This input comes from the DRAC. If the actual speed signal is different from the speed that was sent into and remembered by the module, the module generates pulses to change the vacuum and return the vehicle to the set speed. Other inputs to the module are from the Cruise Switch and the Set Switch. A disconnect input to the module comes from a switch on the brake pedal and on vehicles equipped with a manual transmission, from the Clutch Switch. A separate vacuum shut-down of the Cruise Control comes from the Brake/Clutch Cruise Release Valve on the brake pedal. The two outputs of the Cruise Control Module operate the coils of the Vacuum Valve and the Vent Valve. Both valves are located in the Cruise Control Servo. These valves move the throttle by means of the Vacuum Motor. The Servo Position Sensor coil senses the position and motion of the Vacuum Motor. It feeds this information back to the module to provide smooth acceleration while the vehicle is in Cruise Control. DIAGNOSIS - CRUISE CONTROL CRUISE CONTROL DOES NOT DISENGAGE WHEN CLUTCH OR BRAKE PEDAL IS DEPRESSED TEST 1. Place ignition switch in RUN and cruise control switch to ON. Connect a test lamp from GRA (397) wire at brake switch connector C253 to ground. RESULT GO to step 2, (man trans). GO to step 5 (auto trans). Test lamp does not light. LOCATE and REPAIR open in GRA (397) wire between brake switch and cruise control switch. 2. Connect a test lamp from BRN (86) wire at brake switch connector C253 to ground. Do not depress brake pedal. Test lamp lights. GO to step 3. Test lamp does not light. CHECK adjustment of brake switch. If brake switch cannot be adjusted, REPLACE brake switch. 3. Connect a test lamp from BRN (86) wire at clutch switch connector C254 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BRN (86) wire between brake switch and clutch switch. 4. Connect a test lamp from GRA/BLK (87) wire at clutch switch connector C254 to ground. Do not depress clutch pedal. Test lamp lights. REFER to "Cruise Control Does Not Operate" procedure. 5. Connect a test lamp from GRA/BLK (87) wire at brake switch connector C253 to ground. Do not depress brake pedal. A-122 CRUISE CONTROL CHECK adjustment of clutch switch. If adjustment cannot be corrected, REPLACE clutch switch. Test lamp lights. REFER to "Cruise Control Does Not Operate" symptom. Test lamp does not light. CHECK adjustment of brake switch. If adjustment cannot be made, REPLACE brake switch. ACTION 1. Place ignition switch in RUN and cruise control switch to ON. Connect a test lamp from GRA (397) wire at cruise control switch connector C252 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PNK/BLK (139) wire between cruise control switch and fuse block. If wire is in good condition, REPLACE cruise control switch. 2. Connect a test lamp from DK BLU (84) wire at cruise control switch connector C252 to ground. Test lamp lights. REPLACE cruise control switch. Test lamp does not light. GO to step 3. 3. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in DK BLU (84) wire between cruise control switch and cruise control module. If wire is in good condition, REPLACE cruise control switch. 4. Depress and hold RESUME/ ACCELERATE switch. Connect a test lamp from DK GRN (83) wire at cruise control module connector C252 to ground. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in DK GRN (83) wire. If wire is in good condition, REPLACE cruise control switch. 5. Connect a test lamp from GRA (397) wire at cruise control module connector C252 to ground. Test lamp lights. GO to step 6. Test lamp does not light. LOCATE and REPAIR open in GRA (397) wire between cruise control module and brake switch and/or brake switch and cruise control switch. 6. Connect a test lamp from BLK (150) wire to GRA (397) wire at cruise control module connector C252. Test lamp lights. GO to step 7. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire between cruise control module and bus bar ground. 7. Place ignition switch to OFF. Disconnect cruise control servo connector C184. Using four jumper leads, connect cavities A, B, D and E to ground. Using a digital ohmmeter, check for continuity in DK BLU/WHT (403), TAN (398), LT BLU/BLK (399) and LT GRN (402) wires at cruise control module connector C252 to ground. No continuity in any or all wires. LOCATE and REPAIR open in wire(s) that show no continuity. Continuity. GO to step 8. Depress SET/COAST switch. Connect a test lamp from DK BLU (84) wire at cruise control module connector C252 to ground. ACTION Test lamp lights. Test lamp does not light. RESULT TEST CRUISE CONTROL DOES NOT OPERATE (CONTINUED) RESULT TEST 8. Connect a digital ohmmeter at BLK (150) cavity in cruise control servo connector C184 and check for continuity to ground. ACTION No continuity. LOCATE and REPAIR open in BLK (150) wire between cruise control servo and bus bar ground. Continuity. Problem is not related to the cruise control system wiring or switches, replace cruise control module and test drive. If still inoperative, replace cruise control servo. CRUISE CONTROL A-123 RPO CODES LH6 - ENGINE, 6.2L (378 CID) V8 DIESEL ENGINE, VIN C LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE, VIN J -1 i i— j I (LH6, LL4 ONLY) CRUISE CONTROL MODULE C255 12034117 8911256 A-124 CRUISE CONTROL FOUR-WHEEL DRIVE ENGAGES BUT 4WD INDICATOR LAMP DOES NOT LIGHT (V100, V200) CIRCUIT OPERATION When the Ignition Switch is in RUN and the FourWheel Drive Control (4WD) Lever is engaged, the Transfer Case Switch closes and battery voltage is applied across the Front Axle Actuator. The Front Axle Actuator energizes and the four-wheel drive gears are meshed. This meshing action of the four-wheel drive gears closes the Front Axle Switch, and battery voltage is applied through the WHT (156) wire across the fourwheel drive indicator lighting the bulb in Utility and Suburban models. On Fleetside, Wideside and Crew/Bonus Cab models, the closing of the switch provides a ground for the indicator lamp. Battery voltage is also applied through the front axle switch contacts and the PPL (420) wires to the Electronic Rear Wheel Brake Control Module in the Utility and Suburban models. This will keep the antilock braking system disabled in 4WD mode. The In-Line Resistor (automatic transmission only) prevents the TCC Solenoid from engaging when the Front Axle Switch is closed. TEST GO to step 2. Test lamp does not light. CHECK RADIO fuse. If fuse is good, LOCATE and REPAIR open in BRN (141) wire between transfer case switch connector C309 and fuse block connector C288. Connect transfer case connector C309. Connect a test lamp to the WHT (156) wire at the back of the transfer case connector C309 to ground. Place the transfer case in four-wheel drive. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE transfer case switch. 3. With ignition switch in RUN and transfer case in four-wheel drive, disconnect 4WD indictor lamp connector C246. Connect a test lamp between WHT (156) wire and ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in WHT (156) wire between transfer case switch connector C309. and four-wheel drive indicator lamp connector C246. 4. Test lamp lights. REPLACE bulb. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire to ground. 2. PRELIMINARY CHECKS: While performing the following diagnostic procedures, the Ignition Switch must be in RUN, and the 4WD Control Lever must be in the 4WD ENGAGED position. To determine whether the vehicle is in Two-Wheel Drive or Four-Wheel Drive, it must be lifted up so the wheels can spin freely. FOUR-W HEEL D R IV E IN D IC A T O R LAM P W IL L N O T TU R N O FF TEST Disconnect transfer case switch connector C309. RESULT 4WD indicator lamp goes off. ACTION Test lamp lights. 1. DIAGNOSIS - FOUR-WHEEL DRIVE INDICATOR LAMP Make sure all mechanical components are operative before diagnosing the electrical portion of the four-wheel drive system. RESULT Place ignition switch in RUN. Remove transfer case connector C309. Connect a test lamp from BRN (141) wire to ground. Connect a test lamp between WHT (156) wire and BLK (150) wire at four-wheel drive indicator lamp connector C246. ACTION REPLACE transfer case switch. FO U R -W H E E L D R IV E EN G A G ES B U T 4W D IN D IC A TO R LA M P DO ES N O T L IG H T (V 300) TEST 1. 2. 3. 4. RESULT ACTION Disconnect 4WD indicator lamp connector C246. Connect test lamp to BRN/WHT (141) wire to ground. Test lamp lights. GO to step 2. Test lamp does not light. CHECK RADIO fuse, if fuse is good, LOCATE and REPAIR open in BRN/WHT (141) wire. Connect test lamp to connector C246 to BRN/WHT (141) to WHT (156) wire. Engage four-wheel drive. Test lamp lights. REPLACE 4WD indicator lamp. Test lamp does not light. GO to step 3. Connect a self-powered test lamp to WHT (156) wire at transfer case connector C309 to ground. Test lamp does not light. LOCATE and REPAIR open in WHT (156) wire. Test lamp lights. GO to step 4. Test lamp lights. REPLACE transfer case switch. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire to ground. Connect a self-powered test lamp between WHT (156) wire and BLK (150) wire at transfer case switch connector C246. Make sure fourwheel drive is engaged. FOUR-WHEEL DRIVE A-125 C288 12004887 43*.8 YEL 0 0 0 0 L iG N ^f SHUNT SHUNT ACC LPS El INSTR LPS K l KIGN l AUXKHTR lA/C k f i HMl 3 3 IK K l kQ I kQ I k® HORN/DM T/L CTSY GAGE/IDLE HTR A/C 30 A ECM B TURN B/U PWR WDO to t I kB I kH IK KECM 1l DDRLd B 'f l DC 0 □ □D FRONT B^S o ) ] REAR FUSE BLOCK 12103404 I 141-.8 BRN/WHT FOUR-WHEEL DRIVE INDICATOR LAMP n E IF ill (ft) If ^T1 TRANSFER CASE SWITCH (CLOSED INFOURWHEEL DRIVE) TRANSFER CASE SWITCH FOUR-WHEEL DRIVE INDICATOR W/RWAL A-126 FOUR-WHEEL DRIVE (CLOSED IN FOURWHEEL DRIVE) 13 FOUR-WHEEL DRIVE INDICATORS W/O RWAL BUS BAR GROUND G200 DIAGNOSIS — POWER MIRRORS CIRCUIT OPERATION PRELIMINARY CHECKS: POWER MIRRORS Voltage is applied at all times to the Power Outside Rearview Mirror Switch, through the HORN/DM Fuse and an In-Line Auto Fuse. The mirror assemblies contain two motors. One motor positions the mirror up and down, the other motor positions the mirror to the left or right. By reversing the polarity of the motors, the motors will move the mirrors either up/down or left/right. POWER DOOR LOCKS When a Door Lock Switch is operated, all of the doors will unlock or lock. Each lock can also be operated manually. The locks are operated by reversible motors that receive voltage from the PWR/ACC Circuit Breaker. The Door Lock Switches operate to turn the Motors on by applying battery voltage to one of the terminals and ground to the other terminal. When either Door Lock Switch is moved to the LOCK position, it completes the circuit to the Motors. Voltage is applied to the GRA (295) wire and to the Door Lock Motors, which are grounded by the TAN (294) wire from the other terminal of the Motor through the other switch contact to ground. The Motor in each door runs to operate the Door Locks. When the Door Lock Switch is released, the circuit is opened and the Motors turn off. A similar action occurs with either of the Door Lock Switches closing to the UNLOCK position. Now the TAN (294) wires to the Motors supply battery voltage and the GRA (295) wires are grounded. The polarity of the voltage to the Motors has reversed. The Motors run in the opposite direction to unlock the doors. The Door Lock Switches are usually closed for just a moment. If the Door Lock Switches are held closed, a circuit breaker in each Motor will open to protect against damage. The circuit breakers close automatically when they cool off. 1. Check to see that the HORN/DM, PWR ACC and in-line (C266) fuses are not blown. If blown, locate and repair source of the overload, then replace fuse. 2. Refer to Section 8 of the 1991 R/V,P Light Truck Service Manual for diagnosis and repair of all nonelectrical system components. NEITHER MIRROR IS OPERATIONAL TEST RESULT 1. Connect test lamp from ORN (40) wire at mirror switch connector C505 to ground. 2. Connect test lamp from ORN (40) wire to BLK (150) wire at mirror switch connector C505. Test lajrnp does not light. Test lamp lights. Test lamp does not light. Test lamplights. ACTION LOCATE and REPAIR open in ORN (40) wire between mirror switch connector C505 and fuse block. GO to step 2. LOCATE and REPAIR open in BLK (150) wire between mirror switch connector C505 and bus bar ground. REPLACE mirror switch. LH MIRROR WILL NOT ADJUST UP AND DOWN TEST RESULT Disconnect in-line fuse connector C266 and connector C504 at LH mirror motor. Place ohmmeter on Rx1 scale and connect leads to YEL (88) and LT BLU (82) wires at LH mirror motor connector C504. While holding mirror adjustment switch in the UP and DOWN positions, measure for continuity. ACTION Continuity. REPLACE LH mirror motor. No continuity. LOCATE and REPAIR open in YEL (88) or LT BLU (82) wires between mirror switch connector C505 and LH mirror motor connector C504. If none if found, REPLACE switch. LH MIRROR WILL NOT ADJUST LEFT AND RIGHT TEST RESULT Disconnect in-line fuse connector C266 and connector C504 at LH mirror motor. Place ohmmeter on Rx1 scale and connect leads to WHT (81) and LT BLU (82) wires at LH mirror motor connector C504. While holding mirror adjustment switch in the LEFT and RIGHT positions, measure for continuity. Continuity. No continuity. ACTION REPLACE LH mirror motor. LOCATE and REPAIR open in WHT (81) or LT BLU (82) wires between mirror switch connector C505 and LH mirror motor connector C504. If none is found, REPLACE switch. POWER MIRROR AND POWER DOOR LOCKS A-127 RH MIRROR WILL NOT ADJUST UP AND DOWN Disconnect in-line fuse connector C266 and connector C600 at RH mirror motor. Place ohmmeter on Rx1 scale and connect leads to YEL/BLK (888) and LT BLU/BLK (82) wires at RH mirror motor connector C600. While holding mirror adjustment switch in the UP and DOWN positions, measure for continuity. REPLACE RH mirror motor. Continuity. No continuity. TEST ACTION RESULT TEST ONE DOOR LOCK MOTOR DOES NOT LOCK OR UNLOCK FROM A PARTICULAR SWITCH LOCATE and REPAIR open in YEL/BLK (888) and LT BLU (82) wires between mirror switch connector C505 and RH mirror motor connector C600. If none is found, REPLACE switch. 1. Connect a test lamp from ORN/BLK (60) wire at inoperative switch connector to ground. 2. RH MIRROR WILL NOT ADJUST LEFT AND RIGHT Disconnect in-line fuse connector C266 and C600 at RH mirror motor. Place ohmmeter on Rx1 scale and connect leads to WHT/BLK (881) and LT BLU/BLK (82) wires at RH mirror motor connector C600. While holding mirror adjustment switch in the LEFT and RIGHT positions, measure for continuity. REPLACE RH mirror motor. Continuity. No continuity. 3. LOCATE and REPAIR open in WHT/BLK (881) and LT BLU/BLK (82) wires between mirror switch connector C505 and RH mirror motor connector C600. If none is found, REPLACE switch. 1. NONE OF THE DOOR LOCK MOTORS LOCK OR UNLOCK Connect test lamp from ORN/BLK (60) wire at door lock relay connector C264 to ground. ACTION RESULT Test lamp does not light. Test lamp lights. LOCATE and REPAIR open in ORN/BLK (60) wire between switch and splice S259. Test lamp lights. If door lock will not lock, go to step 2. If door lock will not unlock, go to step 3. Door lock motor runs. REPLACE door lock switch. Door lock motor does not run. LOCATE and REPAIR open in LT BLU (195) wire between inoperative switch connector and door lock relay connector C264. Door lock motor runs. REPLACE door lock switch. Door lock motor does not run. LOCATE and REPAIR open in BLK/WHT (194) wire between inoperative switch connector and door lock relay connector C264. ONE DOOR LOCK MOTOR DOES NOT OPERATE FROM ANY SWITCH TEST DIAGNOSIS — POWER DOOR LOCKS TEST Connect a fused jumper from ORN/BLK (60) wire to BLK/WHT (194) wire at inoperative switch connector. LOCATE and REPAIR open in ORN/ BLK (60) wire between door lock relay connector C264 and fuse block. Inspect splice S259 for open wire. If no open is found, REPLACE PWR ACC circuit breaker. INSPECT door lock relay for poor ground condition or REPLACE door lock relay. A-128 POWER MIRRORS AND POWER DOOR LOCKS ACTION Test lamp does not light. ACTION RESULT TEST Connect a fused jumper from ORN/BLK (60) wire to LT BLU (195) wire at inoperative switch connector. RESULT 2. Connect test lamp from TAN (294) wire to GRA (295) wire at inoperative motor and momentarily place door lock switch in lock or unlock position while observing test lamp. Connect test lamp from TAN (294) wire at inoperative motor to ground and momentarily place door lock switch to unlock position while observing test lamp. RESULT ACTION Test lamp lights. REPLACE door lock motor. Test lamp does not light. GO to step 2. Test lamp lights. LOCATE and REPAIR open in GRA (295) wire between inoperative motor connector and spliceS258. Test lamp does not light. LOCATE and REPAIR open in TAN (294) wire between inoperative motor connector and splice S257. w v w w w w m S HOT AT ALL TIM ES < Z'VM/VWVWWN I 640-1.0 ORN HORN/DM 20 AMP § f 0 * BATj^ i i @ 0 /[c] 0 ® E / [cf @ WDO |c ] [a ) [a ] MGN^J m [D] ACC LPS SHUNT SHUNT D H 5RN3 /bl4l GAGE/IDLE HTR A/C \S ] \ . TURN B/U PWR WDO K j ECM 1 K ] DRL Kl 0□ FRONT 40-.5 ORN 150-.5 BLK I 40-.5 ORN LEFT/RIGHT s = i ' C266 12010105 IN-LINE 3 AMP AUTO FUSE POWER WINDOWS (SEE PAGE 139) BUS BAR __ GROUND TT] 31 G201 POWER OUTSIDE REARVIEW MIRRORS A-129 t ^ -----1l 2 I ? ' M 5 LH DOOR LOCK MOTOR A-130 POWER DOOR LOCKS 2-DOOR (WITHOUT POWER OUTSIDE REARVIEW MIRRORS) 0 [c] 0 @ 1] @ i B ”fcAR m m 0 0 1 0 ® t-B A T -* @ WDO 0 B U M G N ^f SHUNT ACC i Gj]Ha LPS BS B d T /L CTSY K l ECM B PWR |sHUNT [ 'sA* | INSTR LPS H O R N /D M O PW R A C C K l K l K IG N A U X HTR A /C H E G A G E /ID L E STO P HA I K HTR A /C BdDL T U R N B /U PW R W D O KE C M l1 KDRL l RADIO n»n WIPER q Cd 0 □ FRONT D OOR LOCK RELAY i “ • -------------- l l 2 X T ' -------------------m m 5 LH DOOR LOCK MOTOR POWER DOOR LOCKS A-131 2-DOOR (WITH POWER OUTSIDE REARVIEW MIRRORS) RH FRONT DOOR LOCK MOTOR [c] (c) 0 T 0 0 0 l 0 m M il 0 (W) 0 0 WDO 0 I batj 0 HGN^ SHUNT MM 0 0 0 0 SH UN T ACC LPS P iA ^ j UE INSTR LPS HORN/DM Kl Kl kfi BkA K l Kl K VE Is T IGN AUX HTR A/C T/L CTSY GAGE/IDLE HTR A/C 30 kECM Bi B d I UE I VE A TURN B/U PWR WDO K J KDHL] ECM 1 B 'fl S'S Kl □0 0 D 0/fi CRANK FRONT 60-2.0 GRN/BLK ll 195-.8 LT ■ r jm v .m v ^ 194 -. a b lk / w h t ^ .^ b v j h t ^m a r > 12020398 12015344 LH DOOR LOCK SWITCH A B C nn— nn 0) (O •Ik U1 0 <0 UNLOCK 12020397 TT LOCK’ GT500 GT501 8911670 L = 12010247 194-.8 LT BLU H ■ i^ ^ ^ B H 1 9 4 - .8 L T B L U 60-2.0 ORN/BLK I W 195-.8 BLK/WHT ■ r ^■■60-2.0 O R N /B LK iv 295-1.0 GRA 295-1.0 GRA I 294-1.0 TAN H H 1 294-1.0 TAN A-132 POWER DOOR LOCKS 4-DOOR (WITH POWER OUTSIDE REARVIEW MIRRORS) K A JI ^ii95-.8 BL-K/WHT^*"^' LH FRONT DOOR LOCK MOTOR GT800 12010366 I 295-1.0 GRA I 295-1.0 GRA I 294-1.0 TAN 294-1.0 TAN i i i 295 { 294 .. RH REAR DOOR LOCK MOTOR C802 12004140 12015344 SIDE DOOR CONTACT BUTTONS REAR PANEL DOOR LOCK MOTOR C402 I 295-1.0 GRA | 295-1.0 GRA I 294-1.0 TAN I 294-1.0 TAN 295-1.0 GRA 294-1.0 TAN C404 I 294-1.0 TAN I 12047676 12020397 | 295-1.0 GRA 1295-1.0 GRA I CONTACTOR I 195-.8 LT BLU I 1194-.8 BLK/WHT I DOOR LOCK RELAY I 295-1.0 GRA I I 294-1.0 TAN I I 294-1.0 TAN | C264 2984378 I I 294-1.0 TAN I I 60-2.0 ORN/BLKI 1295-1.0 GRA I I 195-.8 LT BLU I I 194-.8 BLK/WHT I I A B C 12047675 C403 I 295-1.0 GRA I 294-1.0 TAN H L_ 295 r 294 r LH REAR DOOR LOCK MOTOR GT700 12020366 POWER DOOR LOCKS A-133 4-DOOR (WITH POWER OUTSIDE REARVIEW MIRRORS) RH FRONT DOOR LOCK MOTOR LH FRONT DOOR LOCK MOTOR A-134 POWER DOOR LOCKS 4-DOOR (WITHOUT POWER OUTSIDE REARVIEW MIRRORS) GT800 12010366 1 295-1.0 GRA (-1 294-1.0 TAN 295 c 294 L fc = L I [*"'•— CIRCUIT . I B R EA K E R ■ RH DOOR LOCK MOTOR C602 12004140 SIDE DOOR CONTACT BUTTONS REAR PANEL DOOR LOCK MOTOR 295-1.0 GRA 294-1.0 TAN C404 AAA A A t f i 294-1.0 TAN 12047676 12020397 295-1.0 GRA DOOR LOCK RELAY 194-.8 BLK/WHT 295-1.0 GRA ■ ■ ■ ■ 294-1.0 TAN Bl l — 294-1.0 TAN * AA 294-1.0 TAN I I m< 194-.8 BLK/WHT r nn— nn ’ KJ □ 12020397 M „ l n5 GT700 C702 12004140 12020366 295-1.0 GRA 295-1.0 GRA 294-1.0 TAN in 294-1.0 TAN Fn u I"r ?94 r LH REAR DOOR LOCK MOTOR POWER DOOR LOCKS A-135 4-DOOR (WITHOUT POWER MIRRORS) CIRCUIT OPERATION A permanent magnet (PM) motor operates each of the Power Windows. Each Motor raises or lowers the window when voltage is supplied to it. The direction the Motor turns depends on the polarity of the supply voltage. The Switches control the supply voltage polarity. DIAGNOSIS circuit breaker and the ORN/BLK (60) wire. When the ignition switch is in RUN or ACC, battery voltage is applied to the PWR WOO circuit breaker and the PNK (76) wire to the front tailgate window switch. WINDOW SWITCH OPERATION The Master Door Lock/Power Window Switch Assembly controls all of the Window Motors. Each window also has its own control switch. Each Motor is protected by a built-in circuit breaker. If a Window Switch is held too long with the window obstructed or after the window is fully up or down, the circuit breaker opens the circuit. The circuit breaker resets automatically. When the Ignition Switch is in RUN or ACC, battery voltage is applied to the Master Door Lock/Power Window Switch Assembly, the PWR WDO Circuit Breaker, and the PNK (76) wires. When any of the UP Switches are operated, battery voltage is applied to the Window Motor through the DK BLU/WHT (166) wire. The Window Motor is grounded through the DN contact. The Motor runs to drive the window up. When any of the DN Switches are operated, battery voltage is applied to the Window Motor in the opposite direction through the BRN (65) wire. The Window Motor is grounded through the UP contact. The Motor runs to drive the window down. Battery voltage is supplied to the key-operated tailgate window switch at all times through the PWR ACC A-136 POWER WINDOWS When the Ignition Switch is in RUN or ACC, battery voltage is applied to the Window Switch through the PWR WOO Circuit Breaker and the PNK wires to terminal 76. When the UP Switch in the Window Switch is operated, battery volt~ge is applied to the Window Motor through the OK BLU/WHT (166) wire. The Motor is grounded through the BRN (165) wire, the ON contact in the Window Switch, the TAN (167) wire and the ON contact in the Master Door Lock/Power Window Switch Assembly. The Motor runs to drive the window up. When the DN switch in the Window Switch is operated, battery voltage is applied to the Window Motor in the opposite direction through the BRN (165) wire. The Motor is grounded through the OK BLU (164) wire, the UP contact in the Window Switch, the OK BLU/WHT (166) wire and the UP contact in the Master Door Lock/Power Window Switch Assembly. The Motor runs to drive the window down. The tailgate window motor receives voltage from either the front or key-operated tailgate switches through the LT BLU (183) wire for down or the TAN/WHT (184) for up operation. The tailgate window motor is grounded at the tailgate. POWER WINDOWS PRELIMINARY CHECKS: Check condition of PWR WDO circuit breaker. If circuit breaker is in good condition, use the following diagnostic procedures. POWER WINDOWS DO NOT OPERATE OR ONLY GO IN ONE DIRECTION TEST RESULT ACTION 1. Place ignition switch in RUN or ACC position. Connect a test lamp from PNK (76) wire at affected window switch connector C500, C601, C700 or C800 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PNK (76) wire from affected window switch to fuse block. 2. Connect a test lamp from PNK (76) wire to BLK (150) wire at affected window switch connector C500, C601, C700 or C800. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from affected window switch to bus bar ground. 3. Move and hold affected window switch to UP position. Connect a test lamp from BRN (165,667, or 669) wire at affected window switch connector C500, C601, C700 or C800 to ground. Test lamp lights. GO to step 4. Test lamp does not light. REPLACE affected window switch. 4. Connect a test lamp from BRN (165, 667, or 669) wire to OK BLU (164, 666, or 669) wire at affected window switch connector C5 0 0, C601, C700 or C800. Test lamp lights. GO to step 5. Test lamp does not light. REPLACE affected window switch. 5. Connect a test lamp from BRN (165, 667, or 669) wire at affected window motor connector C503, C604, C701 or C801 to ground. Test lamp lights. GO to step 6. Test lamp does not light. LOCATE and REPAIR open in BRN (165, 667 or 669) wire from affected window motor to window switch. 6. Connect a test lamp from BRN (165, 667, or 669) wire to OK BLU (164, 666, or 668) wire at affected window motor connector C503, C604, C701 or C801. Test lamp lights. REPLACE affected window motor. Test lamp does not light. LOCATE and REPAIR open in DK BLU (164, 666 or 668) wire between affected window motor and window switch. POWER WINDOWS ONLY OPERATE FROM DRIVER’S SIDE WINDOW SWITCH TEST 1. Place ignition switch in ACC position. Connect test lamp from PNK (76) wire at affected window switch connector C601, C700 or C800 to ground. 2. Move affected window switch to UP position. Connect test lamp from BRN (667 or 669) wire at affected window switch connector C601, C700 or C800 to ground. 3. Move affected window switch to DOWN position. Connect test lamp from DK BLU (666 or 668) wire at affected window switch connector C601, C700 or C800 to ground. RESULT 8. Connect test lamp from PNK (76) wire to DK BLU/WHT (166), DK GRN (168) or LT GRN (170) wire and then to TAN (167), PPL (169) or PPL/WHT (171) wire at affected window switch connector C601, C700 or C800. ACTION Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PNK (76) wire from affected window switch to fuse block. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE affected window switch. Test lamp does not light. REPLACE affected window switch. 1. Place ignition switch in ACC position. Position and hold affected window switch to UP position. Connect test lamp from BRN (667 or 669) wire at affected window motor connector C604, C701 or C801 to ground. 1. 1. RESULT ACTION Test lamp lights. GO to step 2. Test lamp does not light. GO to step 3. REPLACE affected window motor. Test lamp does not light. GO to step 3. 3. Connect a test lamp from PNK (76) wire at affected window switch connector C506 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in PNK (76) wire from affected window switch to fuse block. 5. Connect test lamp from PNK (76) wire to BLK (150) wire at affected window switch connector C506. LOCATE and REPAIR open in wires (166,168,170,167,169 or 171) from affected window switch to left window switch. Tailgate should remain closed t hroughout the diagnosis of the POWER REAR WrINDOW circuit. TEST Test lamp lights. 4. Connect test lamp from PNK (76) wire to DK BLU/WHT (166), DK GRN (168) or LT GRN (170) wires at affected window switch connector C506. Test lamp lights at only one wire or not at all. 2. CHECK condition of PWR WDO and PWR ACC circuit breakers. If circuit breakers are in good condition, use the following diagnostic procedures. TAILGATE WINDOW DOES NOT OPERATE FROM FRONT TAILGATE WINDOW SWITCH Connect test lamp from BRN (667 or 669) wire to DK BLU (666 or 668) wire at affected window motor connector C604, C701 or C801. 2. REPLACE affected window switch. PRELIMINARY CHECKS: POWER WINDOWS DO NOT OPERATE FROM DRIVER’S SIDE WINDOW SWITCH TEST Test lamp lights at all wires. Test lamp lights. GO to step 6. Test lamp does not light. GO to step 5. Test lamp lights. REPLACE affected window switch. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from affected window switch to bus bar ground. 6. Connect test lamp from PNK (76) wire to TAN (167), PPL (169) or PPL/WHT (171) wire at affected window switch connector C506. Test lamp lights. GO to step 8. Test lamp does not light. GO to step 7. 7. Connect test lamp from PNK (76) wire to BLK (150) wire at affected window switch connector C506. Test lamp lights. REPLACE affected window switch. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from affected window switch to bus bar ground. 2. 3. 4. 5. 6. RESULT ACTION Place ignition switch in RUN or ACC position. Connect a test lamp from PNK (76) wire at front tailgate window switch connector C274 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PNK (76) wire from front tailgate window switch connector C274 to fuse block. Position and hold tailgate window switch in the UP position. Connect a test lamp from TAN/WHT (184) wire at front tailgate window switch connector C274 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE front tailgate window switch. Position and hold front tailgate window switch in the DOWN position. Connect a test lamp from LT BLU (183) wire at front tailgate window switch connector C274 to ground. Test lamp lights. GO to step 4. Test lamp does not light. REPLACE front tailgate window switch. Connect a fused jumper from PNK (76) wire at the front tailgate window switch connector C274 to TAN/WHT (184) wire. Then connect a test lamp from TAN/WHT (184) wire at tailgate window motor connector C905 to ground. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in TAN/WHT (184) wire between tailgate window motor connector C905 and front tailgate window switch. Connect a fused jumper from PNK (76) wire at the front tailgate window switch connector C274 to LT BLU (183) wire. Then connect a test lamp from one LT BLU (183) wire at cutout switch connector C904 to ground. REPEAT for the other LT BLU (183) wire. Test lamp lights at both wires. GO to step 6. Test lamp does not light at one or both wires. LOCATE and REPAIR open in LT BLU (183) wire from cutout switch connector C904 to front tailgate window switch connector C274. If wire is in good condition, REPLACE cutout switch. Connect a test lamp from LT BLU (183) wire at tailgate window motor connector C905 to ground. Test lamp lights. REPLACE tailgate window motor. Test lamp does not light. LOCATE and REPAIR open in LT BLU (183) wire between tailgate motor connector C905 and cutout switch. If wire is in good condition, REPLACE tailgate window motor. POWER WINDOWS A-137 ____________ RPO CODES____________________ 76 -2.0 p n k D48 - ELECTRIC REMOTE CONTROL OUTSIDE MIRROR HTR m i (g [c] 0 l [wp’ ® l 0 m « 6ca r m / WDO @ @ 0 0 1 0 ® J L-IG ig N n^ SHUNT SHUNT 1 167-2.0 TAN ACC LPS PWR El w 666-2.0 DK BLU 176-2.0 PNK INSTR LPS PWR ACC HORN/DM J 1 166-2.0 DK BLU/WHT KIGN] AUXKHTR]A/C H STOP HA 667-2.0 BRN GT601 Kl Kl Kl Kl Kl T/L CTSY GAGE/IDLE HTR A/C 30 A ECM B TURN B/U PWR WDO K Kl E 00 ECM 1 DRL CRANK ' 12010247 CD^— t0 - o \ / C [ £ } u)i q S'S S'S □ 0 S'S r O ) A 12015345_ — FRONT C262 — «c -«o= = = t 76 667 166 666 167 r * ___ t RH WINDOW SWITCH 150-2.0 blk FUSE BLOCK m annni n^^r, in ^irsn rr RH WINDOW MOTOR 12004267 G200 POWER WINDOWS A-139 ________________ 2-DOOR___________ 12004884 C259 DOWN UP RH REAR MASTER WINDOW SWITCH n 64-2.0 DK BLU • LH FRONT WINDOW MOTOR A-140 POWER WINDOWS 4-DOOR RPO CODES D48 - ELECTRIC REMOTE CONTROL OUTSIDE MIRROR □ 0 f— r1 t—- 170-2.0 LT GRN ■ ■ ■ J-JnnLJ 12047675 C402 12015344 DOWN -------------------------------------------------- , -------------------- -- IUP ^ I k S261 (D48 ONLY) 1150-3.0 BLKl 1150-.8 BLK I ^ • 76 i 669 170 668 76 669 170 668 i6 8 - o - - ..—-...• . 4 171 r RH REAR WINDOW SWITCH POWER OUTSIDE REARVIEW MIRRORS (SEE PAGE 127) s ffi 12047675 C403 12015344 GT700 FTVUFTl 1 76-2.0 PNK ■ ■ ■ 76-2.0 PNK 1169-2.0 P P L M H 169-2.0 PPL 1 168-2.0 DK GRN I 168-2.0 DK GRN DOWN C D ^—tO— up 169 LH REAR WINDOW SWITCH T C257 12004267 BUS BAR GROUND G201 POWER WINDOWS A-141 (4-DOOR) CUTOUT SWITCH 183-3.0 LT BLU 183-3.0 LT BLU I 183 C904 12004480 (OPENS WHEN WINDOW FULLY UP OR DOWN) (SUBURBAN ONLY) 183-3.0 LT BLU TAIL GATE WINDOW MOTOR 184-3.0 TAN/WHT 183-3.0 LT BLU 184-3.0 TAN/WHT (UTILITY ONLY) TAIL GATE WINDOW SWITCH (KEY OPERATED) 60-3.0 ORN/BLK 184-3.0 TAN/WHT MOTOR BRAKE GROUND G904 A-142 POWER REAR WINDOW CIRCUIT OPERATION PANEL LAMP DOES NOT COME ON TEST The RADIO Fuse provides main power to the Radio. With Ignition Switch in ACC or RUN, voltage is applied through the RADIO Fuse and the YEL wire to the On/Off Switch in the Radio. The On/Off Switch is located in the Radio. The circuit is grounded at Bus Bar Ground. With the On/Off Switch closed, voltage is applied to the SolidState Radio circuits to ground. Two wires connect each speaker to the Radio. The ETR Radio has two inputs that other models do not have: Display Dim Signal and Clock Power. stations can be stored in the electronic memory. The ETR model also provides a digital display of time or station frequency. As in other models, the Panel Lamp Switch controls panel lamp dimming. In the ETR model, dimming is also controlled by the Radio itself by means of the DIM Display Input Signal. The ETR model’s Clock memory and Radio and memory functions are supplied voltage at all times through the HORN/DM Fuse. If voltage to the ETR model is cut off - by disconnecting the Battery, for example - the operator must reset the memory functions when voltage is restored. The ETR model is an AM/FM Radio that changes stations electronically. The frequency of preselected 1. RESULT Disconnect radio connector C241. Place light switch to PARK and panel dimmer switch to HIGH. Connect a voltmeter from GRA (8) wire at radio connector C241 to ground. Battery voltage. ACTION REMOVE radio and send in for service. No voltage. CHECK condition of INST LPS fuse. If fuse is good, LOCATE and REPAIR open in GRA (8) wire from radio to fuse block. DISPLAY DIMMING FUNCTION WILL NOT OPERATE RESULT TEST 1. DIAGNOSIS -- RADIO Disconnect radio connector C204. Place light switch to PARK. Connect voltmeter from BRN (9) wire at radio connector C204 to ground. ACTION Battery voltage. REMOVE radio and send in for service. No voltage. LOCATE and REPAIR open in BRN (9) wire from radio at light switch. RADIO DOES NOT APPEAR TO WORK (NO DISPLAY LIGHTS, NO SOUND) TEST RESULT ACTION NO SOUND OR DISTORTED SOUND FROM A SPEAKER 1. 2. Disconnect radio connector C241 and place ignition switch to RUN or ACC. Connect a voltmeter from YEL (43) wire at radio connector C241 to ground. Battery voltage. GO to step 2. No voltage. CHECK condition of RADIO fuse. If fuse is good, LOCATE and REPAIR open in YEL (43) wire. Connect a voltmeter from YEL (43) wire to BLK (150) wire at radio connector C241. Battery voltage. REMOVE radio and send in for service. No voltage. LOCATE and REPAIR open in BLK (150) wire from radio to bus bar ground. RESULT TEST 1. 2. ACTION Disconnect suspected speaker connector. Set analog ohmmeter on RX1 scale. Connect an ohmmeter across speaker terminals. Speaker pops. GO to step 2. No noise. REPLACE speaker. Place ignition switch to RUN or ACC and turn radio ON. Tune radio to a strong signal. Connect a voltmeter across outputs for suspect speaker. Varying around 1 volt AC. REPLACE speaker. No voltage or greater than 1 volt AC. LOCATE and REPAIR speaker wires between radio and speaker. If wires are good, REMOVE radio and send in for repairs. CLOCK DOES NOT OPERATE TEST 1. Disconnect radio connector C204. Connect a voltmeter form ORN (40) wire at radio connector C204 to ground. RESULT ACTION Battery voltage. REMOVE radio and send in for service. No voltage. CHECK condition of HORN/DM fuse. If fuse is good, LOCATE and REPAIR open in ORN (40) wire. RADIO A-143 RADIO RECEIVER BUS BAR GROUND G200 A-144 AM RADIO MONAURAL RPO COOES HOT AT ALL TIMES ■ UM6 - RADIO, ETR AM/FM STEREO, CASSETTE RH REAR SPEAKER C440 12077787 C439 12077787 LIGHT SWITCH LH REAR SPEAKER RADIO A-145 AM/FM STEREO CIRCUIT OPERATION DIAGNOSIS — REAR DEFOGGER With the Ignition Switch in RUN, voltage is applied to the Rear Defogger Switch. When the Rear Defogger Switch is moved to the ON position, voltage is then applied to the Rear Defogger Timer-Relay. The contact closes, which provides voltage to the ON Indicator and the Rear Defogger. The rear window will become warm to remove fog from the surface of the window. The first time the Rear Defogger Switch is activated, the Timer-Relay will allow the Rear Defogger to operate for 10 minutes. Each time after the Rear Defogger Switch is activated, the Timer-Relay will allow the Rear Defogger to operate for a maximum of five minutes. The Timer-Relay will reset to 10 minutes when the Ignition Switch is turned OFF and then back to the RUN position. The contact in the Rear Defogger Control will stay closed until the Rear Defogger Control Switch is turned off, or the timer cycle is complete. The Timer also shuts off at any time the Rear Defogger Control On-Off Switch is depressed to OFF. REAR WINDOW DEFOGGER DOES NOT WORK AND ON INDICATOR DOES NOT LIGHT TEST RESULT ACTION 1. Place ignition switch in RUN position. Connect a test lamp from ORN/BLK (60) at timer relay connector C279 to ground. Test lamp lights. GO to step 2. Test lamp does not light. CHECK condition of PWR ACC circuit breaker. If circuit breaker is good, LOCATE and REPAIR open in ORN/BLK (60) wire. 2. Connect a test lamp from PNK/BLK (39) wire at rear window defogger switch connector C278 to ground. Test lamp lights. GO to step 3. Test lamp does not light. CHECK condition of IGN fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire. Connect a test lamp from PNK/BLK (39) and BLK (150) wires at rear window defogger switch connector C278 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire. Place rear window defogger switch on and hold. Connect a test lamp from LT BLU (292) wire at rear window defogger switch connector C278 to ground. Test lamp lights. GO to step 5. Test lamp does not light. REPLACE rear window defogger switch. Test lamp does not light. REPLACE timer relay. 3. 4. 5. Place rear window defogger switch ON and hold. Connect a test lamp from PPL/WHT (293) connector at timer relay to ground. ON INDICATOR WORKS BUT REAR WINDOW DEFOGGER DOES NOT DEFROST TEST 1. 2. RESULT ACTION Place ignition switch in RUN and rear defogger switch ON. Connect a test lamp from PPL (293) wire to ground (tailgate models) or PPLVWHT (293) wire at rear window defogger to ground (panel door models). Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PPL or PPL/WHT (293) wires. Connect a test lamp from PPL (293) to ground wires at rear window defogger (tailgate models) or PPL/WHT (293) (panel door models) to BLK (150) wires at rear window defogger, ground G411. Test lamp lights. REPAIR rear defogger as required. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire. REAR DEFOGGER PANEL LAMP DOES NOT WORK TEST Turn headlamps ON and position dimmer control to BRIGHT. Connect test lamp from GRA (8) wire at rear window defogger switch connector C278 to ground. A-146 REAR DEFOGGER RESULT ACTION Test lamp lights. REPLACE panel light bulb. Test lamp does not light. LOCATE and REPAIR open in GRA (8) wire. C212 12059884 r 293-3.0 PPL/WHT 12059885 fc 9 3 j 293-3.0 PPL/WHT 293-3.0 PPL/WHT 293-.S PPL/WHT ________ \ RH DOOR CONTACTOR — A V A V v W /M W — L -A V A W A W A W A — RH REAR WINDOW HEATER REARDEFOGGER A-147 PANEL DOORS 293-.3 PPL I 293-3.0 PPL/WHT C449 C103A 2977976 GT108 8911213 6288585 6288585 2977976 8917583 C912 89177378 I 0- 8 GRAl FRONT FUSE BLOCK REAR WINDOW DEFOGGER SWITCH GROUND JUMPER 293-3.0 PPL/WHT C280 12004201 60-3.0 ORN/BLK * CD BUS BAR GROUND G201 TIMER RELAY 1150-1.0 BLKI P39-.8 PNK/BLK; 148 REAR DEFOGGER TAILGATE dm CIRCUIT OPERATION BACKUP LAMPS PARK, TAIL, MARKER AND LICENSE LAMPS With the Ignition Switch in RUN, or START, voltage is applied through the TURN/BU Fuse to the Transmission Position Switch or the Backup Lamp Switch. Whenever the gear selector lever is shifted to REVERSE the Transmission Position Switch or the Backup Lamp Switch closes and voltage is applied to the Backup Lamps and the Lamps turn on. Voltage is applied through the T/L CTSY Fuse to the Light Switch at all times. With the Light Switch in the PARK or HEAD, voltage is applied to the Park, Tail, Marker, and License Lamps. TRAILER WIRING Trailer wiring is a modification of the existing rear body harness. The trailer lamps operate in the same manner as the vehicle lamps. The trailer lamps are grounded to the vehicle lamps. DIAGNOSIS — REAR EXTERIOR LAMPS REAR TAIL, MA RKER AND LICENSE LAMPS DO NOT OPERATE TEST Test lamp does not light. LOCATE and REPAIR open in BRN (9) wire between light switch connector C202 and connector C300. Test lamp lights. If only RH rear Tail/Marker lamps and license lamps do not operate, GO to step 2. If only LH rear Tail/Marker lamps do not operate, GO to step 3. 2. Test lamp does not light. LOCATE and REPAIR open in BRN (9) wire between connector C300 and RH tail or marker lamp connector C411 or C414. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BRN (9) between LH tail or marker lamp connector C412 or C413 and connector C300. Test lamp lights. Go go step 5. Test lamp does not light. LOCATE and REPAIR open in BLK (150) between tail or marker lamp connector C411, C412, C413 or C414 and G403. Test lamp lights. If rear tail or marker lamp is inoperative, REPLACE bulb. For inoperative license lamps, GO to step 6. Test lamp does not light. LOCATE and REPAIR open BRN (9) wire between license lamp connector and S300 and S404. Test lamp lights. Inspect ground connection at license lamp socket. If satisfactory REPLACE bulb. ground terminals G402 and G403. If only one system is not working, LOCATE and REPAIR an open in the wiring and/or bulbs that pertain to that system. 3. BACKUP LAMPS DO NOT OPERATE TEST 1. 2. 3. 4. RESULT ACTION Place ignition switch to RUN and transmission in reverse. Connect a test lamp from LT GRN (24) wire at backup lamp connector C428 or C429 to ground. Test lamp lights. GO to step 2. Test lamp does not light. GO to step 3. Connect a test lamp from LT GRN (24) wire to BLK (150) wire at backup lamp connector C428 or C429. Test lamp lights. REPLACE bulb. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from backup lamp to ground terminal G403. Connect a test lamp from DK BLU (75) wire at backup lamp switch connector C286 or C118 to ground. Test lamp lights. GO to step 4. Test lamp does not light. CHECK condition of TURN/BU fuse. If fuse is good LOCATE and REPAIR open in DK BLU (75) wire from backup lamp switch connector C286 or C118 to backup lamps. Connect a test lamp from LT GRN (24) wire at backup lamp switch connector C286 or C118 to ground. Test lamp lights. LOCATE and REPAIR open in LT GRN (24) wire from backup lamp switch connector C286 or C118 to fuse block. Test lamp does not light. Adjust backup lamp switch. If backup lamp switch will not adjust properly, REPLACE backup lamp switch. ACTION Place light switch in HEAD or PARK position. If only license lamp does not operate, GO to step 5. Connect a test lamp from BRN (9) wire at connector C300 to ground. 1. PRELIMINARY CHECKS: The rear lamp systems (taillamps, clearance lamps, end gate lamps, and license plate lamps) all receive voltage from same wire circuit BRN (9) and share same RESULT 4. 5. Connect a test lamp from BRN (9) wire at RH tail or marker lamp connector C411 or C414 to ground. Connect a test lamp from BRN (9) wire at inoperative LH tail or marker lamp connector C412 or C413 to ground. Connect a test lamp from BRN (9) wire and BLK (150) wire at inoperative tail or marker lamp connector C411, C412, C413 or C414. Connect a test lamp from BRN (9) wire at license lamp connector C419, C420 or C421 to ground. REAR LAMPS A-149 RADIO/CLOCK (SEE PAGES 144, 145) I 4 0 .8 ORN LIGHT SWITCH RH SIDE MARKER LAMP (SEE PAGE 156) T/L CTSY 20 AMP ywwwwww S 156 HOT A T A L L T M E S ? mwwwwvs C411 8911035 RH TAIL, STOP AND TURN LAMP C ji 9-.8BRN 9-.8BRN p 29 15 N 9 39 14 M I 12 J L 3 11 420 440 439 806 L 140 2 39 120 31 3 50 436 r 35 2 93 97 422 91 92 6 (m 5300 9-.8BRN 12015024 LH TAIL STOP AND TURN LAMP ■ I9 -.8 BRN I LH SIDE MARKER LAMP (SEE PAGE 156) I9 -.8 BRN I A-150 TAILLAMPS SUBURBAN/UTILITY (Q ) ____ •“ SHEET METAL GROUND G402 SHEET METAL GROUND G403 | I (SUBURBAN) m m C412 8811035 b lk ■ ■ m m RPO COOES RADIO/CLOCK (SEE PAGES 144, 145) R05 - DUAL REAR WHEELS T/L CTSY 20 AMP RH SIDE MARKER LAMP (SEE PAGE 156) 156 RH TAIL, STOP AND TURN LAMP LIGHT SWITCH I I 150-.8BLK RH CLEARANCE LAMPS (R05) (SEE PAGE 156) 11 150-.8 BLK 1 1 9-.S BRN ■ Ll 9-.8 BRN ■ 9- 8 BRN C300 ■M 9-.8B R N M I 19-.8 BRN I LH CLEARANCE LAMPS (R05) (SEE PAGE 156) ■■ 9-.8 BRN ■ I ■ I 150-.8 BLK I ■ I 150-.8 BLK C101 12020099 LH SIDE MARKER LAMP (SEE PAGE 156) SHEET METAL GROUND G403 SHEET METAL GROUND G404 TAILLAMPS A-151 FLEETSIDE AND WIDESIDE w w w vw w w * S HOT A T ALL TIMES < S204 40-.8 ORN | 0 M B M 40-, 8 ORN W W W W W 'T T/L CTSY 20 AMP 44 RADIO/CLOCK (SEE PAGES 144, 145) l/P CTSY LPS | 40-.8 ORN (SEE PAGE 118) Z tr o ■1 150- 2- DOME RH TAIL, STOP AND TURN LAMP CIRCUIT BREAKER* 25 AM P l«l-HEAD -1 OFF ' PARK HEAD LIGHT SWITCH C412 6288424 LH TAIL STOP AND TURN LAMP LH TAIL, STOP, AND TURN LAMP GROUND G406 A-152 TAILLAMPS STEPSIDE FRAME GROUND G405 RH TAIL, STOP, AND TURN LAMP GROUND G407 75-.8 DK BLU I WW WAM < wmm M HOT IN RUN < C286 2973407 24-.8 LT GRN ■ > w w vw * e. TURN/BU 15 AMP 175-.S DK BLU BACKUP LAMP SWITCH (AUTO TRANS ONLY) CLOSED WHEN TRANS IN REVERSE 24 B ~> Ui z © S402 EA l © I i LL REV * o 75 RH TAIL, STOP, TURN AND SIDE MARKER LAMPS (SEE PAGE 150) BACKUP LAMP SWITCH CJD (MAN TRANS ONLY) CLOSED WHEN TRANS IN REVERSE RH BACKUP LAMP 24- 0 LT GRN GT401 8911027 (UTILITY) (SUBURBAN ONLY) 8911028 (SUBURBAN) I 150-.8BLK P 94 29 15 N 9 39 14 M 33 12 L 93 11 I 420 440 439 806 L J 140 2 39 31 3 50 436 35 2 93 97 422 91 92 6 35 r : r 120 C428 8911027 (UnLTTY) z cc (S : 8811028 (SUBURBAN) I 150-.8 BLK C100 1202184 I 150-.8 BLK 24-,8 LT GRN LH BACKUP LAMP I 24-.8LTGRN LH TAIL, STOP, TURN AND SIDE MARKER LAMPS (SEE PAGE 150) l/P GT400 (SUBURBAN ONLY) c 9 120 19 30 18 I 24-.0 LT GRN I 12015798 SHEET METAL GROUND G402 SHEET METAL GROUND G403 BACKUP LAMPS A-153 SUBURBAN/UTILITY RPO CODES LL4 - ENGINE, 6.2L (378 CID) V8 HD DIESEL ENGINE VIN J kAAWWWW \ HOT IN START ? >w w w w v^ TURN/BU 15 AMP I BACKUP LAMP SWITCH 175-.S DK BLU I BACKUP LAMP SWITCH C200 (MAN TRANS ONLY) CLOSED WHEN TRANS IN REVERSE H D 24 B i I i R EV O UK 3U L Z 75 (AUTO TRANS ONLY) CLOSED WHEN TRANS IN REVERSE E (o ) I 24- 8 LT GRN @ I75 -.8 DK BLU RH TAIL, STOP, TURN AND SIDE MARKER LAMPS 150-.8 BLK A J A 12064769 75-. 8 DK BLU — GT101 I 12064740 (SEE PAGE 151) L I -r±K (LL4 ONLY) I24-.8 LT GRN I RH BACKUP LAMP 24-.S LT GRN l/P 150-.8 BLK p 94 29 15 N 9 39 14 M 33 12 J L 93 11 18 120 I 420 440 439 806 L 24-.8 LT GRN 120 31 3 50 75 r 35 2 93 97 24 91 92 1 y 9 140 2 39 I C428 150-.8 BLK I 24-.6 LT GRN I SHEET METAL GROUND G403 A-154 BACKUP LAMPS FLEETSIDE AND WIDESIDE LH BACKUP LAMP LH TAIL, STOP, TURN AND SIDE MARKER LAMPS (SEE PAGE 151) 75-. 8 DK BLU I yw w w w V I HOT IN RUN C 24- 8 LT GRN M ■ ^ y g g C266 l 2973407 w vvw * TURN/BU 15 AMP BACKUP LAMP SWITCH (AUTO TRANS ONLY) CLOSED WHEN TRANS IN REVERSE o > LL \ID UJ z 24 B PART OF LAMP ASSEMBLY E > _ Ul CC 75 24-.8 LT GRN A C118 BACKUP LAMP SWITCH 12015792 RH BACKUP LAMP (MAN TRANS ONLY) CLOSED WHEN TRANS IN REVERSE CO 4; § o I o 24-.S LT GRN I S410 2 o CC P 94 29 15 N 9 39 14 M 33 12 J L 93 18 11 120 I 420 440 2 439 806 39 L 140 120 (J 9 r 31 3 50 436 35 2 93 97 422 91 92 6 12015798 : \ PART OF LAMP ASSEMBLY l/P I 24-.S LT GRN I 150-.8 BLK r LH TAIL, STOP, AND TURN LAMP GROUND G406 150-.8 BLK ■ M Y FRAME GROUND G405 H 2 4 -.8 L T G R N | I RH TAIL, STOP, AND TURN LAMP GROUND G407 LH BACKUP LAMP BACKUP LAMPS A-155 STEPSIDE RADIO/CLOCK (SEE PAGES 144, 145) RH SIDE MARKER LAMP LIGHT SWITCH 0 C414 6294015 BACKUP LAMP (SEE PAGE 153) RH TAIL, STOP ANDTURN LAMP (SEE PAGE 150) 9- .8 BRN 9-.8BRN GT 401 (SUBURBAN ONLY) 12015024 12015798 UCENSE LAMP (SEE PAGE 158) I 9-.S BRN I 9 29 15 39 14 J 12 3 11 I 420 440 439 806 L J 2 39 140 120 31 3 ] 50 436 r 35 2 93 97 422 91 92 6 (D : V 5 CD co S300 9*.8 BRN g 9-.8 BRN GT 400 (SUBURBAN ONLY) * | BACKUP LAMP 150-.8 BLK | (SEE PAGE 153) S405 9-.8 BRN I I S403 • i V I 150-.8 BLK ■ ■ ■ 150-.8 BLK H LH TAIL STOP AND TURN LAMP (SEE PAGE 150) i C413 6294015 I9 -.8 BRN I C101 12020099 A-156 REAR PARK AND MARKER LAMPS SUBURABN/UTILITY LH SIDE MARKER LAMP SHEET METAL GROUND G402 SHEET METAL GROUND G403 RRO CODES 40-.8 ORN S204 0 M RADIO/CLOCK r 40-.8 ORN R05 - DUAL REAR WHEELS WIDESIDE PICK-UP (R05 ONLY) T/L CTSY 20 AMP RH FRONT CLEARANCE LAMP RH REAR CLEARANCE LAMP RH SIDE MARKER LAMP C414 6264015 BACKUP LAMP (SEE PAGE 154) RH TAIL STOP AND TURN LAMP (SEE PAGE 151) LICENSE LAMP (SEE PAGE 158) 94 29 15 9 39 14 33 12 J 11 93 18 24 120 9 30 I420 440 439 806 L 140 31 f D j SO r 9735 93 19 j 91 92 2 ■9-.BBRN 39 120 END GATE IDENTIFICATION LAMPS (SEE PAGE 151) 3 436 2 422 i 6 LH TAIL, STOP AND TURN LAMP (SEE PAGE 151) BACKUP LAMP (SEEPAGE 154) t/P 19-. 8 BRNI LH FRONT CLEARANCE LAMP ■WIDESIDE PICK-UP ■ (R05 ONLY) LH REAR CLEARANCE LAMP LH SIDE MARKER LAMP SHEET METAL GROUND G403 REAR PARK AND MARKER LAMPS A-157 FLEETSIDE AND WIDESIDE RADIO/CLOCK (SEE PAGES 144, 145) 40-.8 ORN l/P CTSY LPS (SEE PAGE 118) LIGHT SWITCH RH SIDE MARKER LAMP | (SEE PAGE 156) | T/L CTSY 20 AMP 1150-.8 B L K M yvwvwwwv/ S D H O TATALLTN ES < C202 12004628 Ta w w w v w v n 150- - 156 DOME 2I C1RCUIT BREAKER 2$ A M P 1 9-.8 BRN H (SUBURBAN) OFF RH TAIL, STOP AND TURN LAMP ' PARK I * HEAD -10 (SEE PAGE 156) OFF 40- 'P A R K HEAD 9-.8 BRN I RADIO/CLOCK (SEE PAGES 144, 145) 9-.8 BRN I § o LICENSE LAMP o VP 9-.8BRN cc .cl I 420 440 439 806 D L 140 31 3 ] 50 436 r 30 2 39 : 120 35 2 93 97 422 91 92 6 9- 8 BRN ■ 33 12020184 C100 LH TAIL, STOP AND TURN LAMP (SEE PAGE 156) 19 -8 BRN I 150-.8 BLK m (SUBURBAN) I9-.8 BRN I [I L 9 120 19 30 18 24 LH SIDE MARKER LAMP (SEE PAGE 156) I9 -.8 BRN I C101 12020099 A-158 LICENSE LAMP SUBURBAN/UTILITY SHEET SHEET METAL METAL GROUND GROUND G402 G403 LICENSE LAMP A-159 FLEETSIDE AND WIDESIDE __________ RPO CODES TP2 - AUXILIARY BATTERY BATTERY JUNCTION BLOCK Z cc 0 *o (W/OTP2) r TAIL, STOP ■ TURN SIG, MARKER AND BACKUP LAMPS z X o (W/O TP2) — oj cn |J jtO ) ( 0 7 IN-LINE FUSE 30 AMP BATTERY JUNCTION BLOCK Q D I C300 'S'C D IN-LINE FUSE (30 AMP) O O 47-3.0 DK BLU- AUX 2-5.0 RED- POWER FEED 2-5.0 RED- POWER FEED 24-.8 LT GRN- BACKUP LAMP 9-.8 BRN- TAIL AND UCENSE LAMP 24-.A LT GRN- BACKUP LAMP 18-.8 YEL- LH STOP AND TURN SIG LAMP S-.8 BRN- TAIL AND LICENSE LAMP TRAILER 19-.8 DK GRN- RH STOP AND TURN SIG LAMP 18-.8 YEL- LH STOP AND TURN S/G LAMP t0-.8 DK GRN- RH STOP ANO TURN S/G LAMP IN-LINE FUSE 30 AMP BATTERY JUNCTION BLOCK (W/TP2) FRAME GROUND G403 REAR LAMP CONNECTOR 19-.8 DK GRN REAR LAMP CONNECTOR 24-.S LT GRN C101 12020099 18-.8 YEL ■ ■ 9-.8 BRN ■ ■ CAMPER EQUIPMENT A-160 CAMPER AND TRAILER WIRING 22-5.0 WHT- GROUND IN-LINE FUSE (30 AMP) BATTERY JUNCTION BLOCK (W/TP2) C101 12020099 FRAME GROUND G403 19-.8 DK GRN 24-.S LT GRN B-.8 BRN 18-.8 YEL HEAVY DUTY TRAILER TAIL, STOP TURN SIG, MARKER AND BACKUP LAMPS DIAGNOSIS Conditions most likely to cause vacuum system problems include hoses that leak or become disconnected. With the engine running, either condition is easily detected from the hiss of air at the opening. Other common vacuum problems are kinked or obstructed hoses, hoses connected incorrectly or binding components. A vacuum pump can be used as a vacuum source to operate components and test the system. The built-in vacuum gage of the pump provides a means of checking for a vacuum leak as well. Once vacuum is applied to operate the component, the gage should hold steady until the vacuum is purposely released. On vacuum system that are controlled by electrical or electronic switches, check for a blown fuse, wiring that is cracked, frayed or burned, and high resistance in connectors of the control circuits) before checking for a suspected vacuum system problem. DIAGNOSIS - AUXILIARY HEATER VACUUM CONTROL PRELIMINARY CHECKS: With the engine warmed up and running, verify that the front heater can deliver a strong flow of heated air from the floor outlets with the blower switch on “HI," the mode selector set for heater operation and the temperature lever in the full "HOT" position. If the front heater or A/C heating system is functioning correctly but the auxiliary heater does not, the problem is in the auxiliary heater system. The following procedure will isolate the cause. LITTLE OR NO HEAT FROM AUXILIARY HEATER RESULT TEST 1. With the engine running and the auxiliary heater “OFF,’’move the auxiliary heater control rocker switch to “ LO” and then to “ HI,” pausing to listen for a change in the force of the airflow from the heater outlet with the change. No airflow (or improper airflow). 2. With the engine running and the auxiliary heater switch in “ LO,” disconnect the vacuum hose at the hot water valve and feel for vacuum at the hose end. No vacuum. Vacuum. 3. Disconnect the hot water valve vacuum hose at the auxiliary heater control switch and feel for vacuum at the open port of the switch. No vacuum. 4. Connect all vacuum hoses. With the engine warmed up and running, place the auxiliary heater control switch in “ HI.” After at least a minute of operation in this mode, carefully feel the temperature of the heater inlet pipe downstream from the hot water valve. Proper airflow in both control switch positions. ACTION REFER to Auxiliary Heater Diagnosis in this manaul. GO to step 2. IMPROPER AIR DISTRIBUTION FROM OUTLETS TEST 1. Disconnect the vacuum hose at the actuator for the inoperative air valve (“door”). With the engine idling and the mode lever set in a position that will apply vacuum to the actuator, check for vacuum at the disconnected hose. RESULT Vacuum at or near engine vacuum at idle. Little or no vacuum. ACTION REPAIR binding condition in air valve or linkage. (If no binding is found, REPLACE actuator.) GO to step 2. 2. Disconnect the vacuum hose harness at the rotary selector valve on the A/C control assembly. With the same test conditions as in step 1, check for vacuum at the rotary selector valve port that feeds the suspected vacuum hose. Vacuum at or near engine vacuum at idle. Little or no vacuum. REPAIR obstruction or vacuum leak in hose to the affected actuator. GO to step 3. 3. With the vacuum supply hose disconnected from the rotary selector valve and with the same test conditions as in step 2, check for vacuum at the open end of the tan vacuum supply hose. Vacuum at or near engine vacuum. REPLACE rotary selector valve. Little or no vacuum. REPAIR obstruction or vacuum leak in vacuum supply hose. DIAGNOSIS - CRUISE CONTROL VACUUM HARNESS GO to step 3. GO to step 4. CRUISE CONTROL DOES NOT OPERATE TEST Vacuum. Little or no heat. Adequate heat. REPAIR vacuum source line or REPLACE auxiliary heater control switch, as necessary. REPAIR or REPLACE faulty hot water valve vacuum hose. REPAIR or REPLACE the hot water valve, heater core or heater hoses and pipes as necessary. VERIFY complaint. Vacuum system is OK. DIAGNOSIS - FRONT MANUAL AIR CONDITIONING VACUUM CONTROL PRELIMINARY CHECKS: Use the charts in this section to verify that air is either begin delivered from an outlet when it should not be, or that air is not being delivered when it should be, during operation in one or more modes. After making checks of the vacuum system (listening for the hiss of a vacuum leak, checking for proper vacuum hose connections and kinked, pinched or misrouted hoses), be sure the complaint is not caused by a mechanical problem before making additional vacuum system checks. RESULT ACTION 1. Disconnect vacuum hose (smaller hose) at vacuum valve inlet of servo unit. Connect a vacuum gage to the disconnected hose. Start engine and allow it to idle. Measure vacuum at vacuum hose. Vacuum is less than normal engine vacuum at idle. Vacuum is same as normal engine vacuum at idle. REPAIR vacuum pump (diesel engine) or air leak in hose or connections between cruise control servo and vacuum source (inlet manifold vacuum fitting or vacuum pump). GO to step 2 (gas engine). Verify complaint (diesel engine). 2. Momentarily accelerate engine sharply while watching vacuum gage. Vacuum reduces noticeably as engine accelerates. Vacuum does not change. REPLACE check valve in line from vacuum source. GO to step 3. 3. Stop engine. Disconnect vacuum gage and connect vacuum hose to servo unit. Disconnect vent hose (larger hose) from servo unit and connect a vacuum pump with built-in vacuum gage to the disconnected hose. Operate vacuum pump to obtain the same vacuum as observed in step 1. Stop pumping and observe the vacuum reading. Vacuum drops. REPAIR air leak in hose or connections, or ADJUST or REPLACE vacuum release valve on brake pedal bracket. REFER to Cruise Control Diagnosis in this manaul. Vacuum does not change. VACUUM SYSTEM A-161 CIRCUIT OPERATION AIR DISTRIBUTION VACUUM SYSTEMS A vacuum-operated component uses the force of normal air pressure working against the lower air pressure of a partial vacuum to provide voltage that operates the component. With a gasoline engine, the vacuum created in the inlet manifold when the engine is running is stored in a ball-shaped vacuum tank suspended from the center of the hood inner panel. A check valve in the line feeding vacuum to the tank keeps the stored vacuum from weakening when inlet manifold vacuum drops during high speed or high voltage operation. An engine-driven mechanical vacuum pump serves as the source of vacuum with a diesel engine. A vacuum tank is not required with a vacuum pump. Vacuum is routed through hoses to a mechanical or electric valve that provides a means of controlling the vacuum-operated component. When the valve is open, it allows vacuum to go to an actuator that actually operates the component. When the component is to be returned to its original position, the valve cuts off the vacuum to the actuator hose and vents the hose to normal air pressure. A typical actuator is a metal shell with a movable shaft that retracts and extends to mechanically operate the component. A flexible diaphragm separates the interior of the shell into two chambers - a sealed chamber to which vacuum can be admitted, and an open chamber exposed to normal air pressure. The movable shaft is attached to the center of the diaphragm and extends from the open chamber. When vacuum is directed to the sealed chamber, normal air pressure presses on the other side of the diaphragm and causes it to retract the shaft. When the vacuum is cut off, the sealed chamber is vented to outside air to balance the air pressure on both sides of the diaphragm and eliminate the force that retracted the shaft. A coiled spring within the sealed chamber expands to push the diaphragm back to its original position. This extends the shaft. In addition to the two-position actuator described above, a three-position actuator may be used for certain applications. The three-position actuator has a vacuum hose at each end of the shell. When vacuum is applied to either end of the actuator and the opposite end is vented, the shaft will move in the direction of the end having the vacuum. When both ends of the actuator are vented to normal air pressure, internal springs center the shaft. This provides a center position as well as both extremes for an actuator application that requires three operating positions. The heater and air conditioning actuator of the R/V truck front manual air conditioning system is a three-position actuator. A-162 VACUUM SYSTEM The servo unit of the cruise control is a special type of vacuum actuator with an internal control valve that can apply varying amounts of vacuum to the diaphragm. The varying vacuum provides a calibrated range of throttle positions that can accurately control vehicle speed. The function of the servo is explained more fully under -CRUISE CONTROL VACUUM CONTROL" in this section. AUXILIARY HEATER VACUUM SYSTEM MODE SELECTION UPPER (l/P) A/C OUTLETS LOWER (FLOOR) HEATER OUTLETS DEFROSTER OUTLETS OFF MAX A/C NORM A/C BI-LEVEL V EN T HEAT DEF NONE HIGH HIGH MEDIUM HIGH NONE NONE NONE NONE NONE MEDIUM NONE HIGH LOW NONE NONE NONE NONE NONE LOW HIGH REMARKS: a — Refrigeration system operates. The auxiliary heater control switch in the instrument panel routes battery voltage to the auxiliary heater blower motor when the auxiliary heater control switch is "ON" and the ignition switch is in RUN. In addition, the switch routes vacuum from the vacuum tank to the vacuum actuator that opens the auxiliary heater hot water valve. When open, the hot water valve admits heated coolant to the auxiliary heater inlet pipe and auxiliary heater core. When the auxiliary heater control switch is turned “OFF," electric voltage to the blower motor is cut off and the hot water valve vacuum actuator is vented to atmospheric air to close the valve. This stops the flow of coolant to prevent unwanted heat. FRONT MANUAL AIR CONDITIONING VACUUM SYSTEM The front manual air conditioning system uses vacuum to operate the air valves (“doors") that control airflow through the air conditioning module. Vacuum is supplied from the vacuum tank on the cowl panel in the left corner of the engine compartment. The vacuum supply line brings vacuum to the rotary selectors valve that is operated by the mode lever of the air conditioning control assembly in the instrument panel. A vacuum hose harness brings vacuum from the ports in the rotary selector valve to the vacuum actuators for the air valves of the air conditioning system. All actuators except the heater and air conditioning actuator are twoposition actuators controlled by one vacuum hose. The heater and air conditioning actuator is a three-position actuator with two vacuum hoses. Application of vacuum or vented air to each actuator is determined by the operating mode selected by setting the mode lever in the control assembly. The following charts indicate the air outlets that operate in each mode selection and the response of the rotary selector valve to each mode lever position. b — Inside air recirculated. REMARKS a, b a a c c a c — Refrigeration system off; no air cooling available. ROTARY SELECTOR VALVE OPERATING CHART CONNECTIONS VALVE PORT NO. TERMINAL 1 2 3 4 5 SOURCE A/C MODE HEAT MODE RECIRC & PLENUM DEFROST MODE HOSE COLOR GRA TAN BLUE ORN BLK MODE SELECTION OFF MAX A/C NORM A/C BI­ LEVEL VENT HEAT DEF VAC V EN T VAC VEN T V EN T VAC VAC VENT VAC VENT VAC VAC VENT VENT VENT VAC VENT VENT VENT VEN T VAC VAC VEN T VEN T VEN T VAC VENT VAC VENT VENT VAC VEN T VAC VEN T VAC CRUISE CONTROL VACUUM SYSTEM The cruise control system uses vacuum to operate a servo unit that adjusts throttle position to maintain a desired vehicle speed. The electronic control module of the cruise control system operates a vacuum valve and a vent valve in the servo to trap enough vacuum in the servo to hold the required throttle setting. A vacuum release valve on the brake pedal bracket vents the trapped vacuum to atmosphere when the brake pedal is depressed, allowing the servo to quickly return the throttle to idle. Control Module Functions The cruise control module continually interprets the setting of the mode control switches, the position of the servo linkage to the throttle and the output of the vehicle speed sensor. In response to these inputs, the cruise control module electrically signals the momentary opening or closing of the vacuum and vent solenoid valves in the servo unit. Servo Unit Functions The cruise control servo consists of a vacuumoperated diaphragm, a normally closed solenoid valve to admit vacuum to the servo diaphragm chamber, a normally open solenoid valve to vent the diaphragm chamber to atmosphere, and a variable inductance position sensor that signals the position of the servo linkage - and accordingly, the throttle setting - to the cruise control module. When the system is engaged and operating, the servo operates the throttle as follows: Steady Cruise: Both the vacuum valve and the vent valve are closed, trapping vacuum in the diaphragm chamber to hold a steady throttle setting. Vehicle Losing Speed: The cruise control module opens the vacuum valve to increase the strength of the vacuum in the diaphgram chamber. The vent valve remains closed. Vehicle Gaining Speed: The cruise control module opens the vent valve to the atmosphere to reduce the vacuum in the diaphragm chamber so the throttle return spring can take over and reduce the throttle opening. The vacuum valve remains closed. The cruise control module pulses the opening of the vacuum valve or the vent valve for minor speed corrections until the vehicle reaches the set speed. Under normal road load conditions, the vacuum valve will remain completely open, instead of pulsing, when vehicle speed drops 5 mph below the set speed. When the vehicle speed exceeds 3 mph over the set speed, the vent valve will remain completely open, instead of pulsing. The servo will go into a completely open vent valve position, returning the throttle to idle, when the brake or clutch pedal is depressed, when electrical voltage to the system is lost (such as when the cruise control switch or the ignition switch is turned off) or when there is an open in the variable inductance position sensor coil in the servo. CIRCUIT OPERATION POWER BRAKE BOOSTER VACUUM SYSTEM The power brake booster is a tandem diaphragm vacuum-suspended unit. When the engine is running, inlet manifold vacuum is transmitted to the booster unit through a vacuum hose. A check valve at the power brake booster end of the hose keeps air from flowing from the hose into the booster unit and weakening the power brake operating force when inlet manifold vacuum is low. With the service brakes released, vacuum is supplied equally to both sides of the two diaphragms in the booster unit. JJecause pressure on both sides of the diaphragms are balanced, no boost is provided to the braking system and the brakes are not applied. When the driver presses down on the brake pedal, the pedal pushrod depresses a spring-loaded air valve within the power brake booster. The air valve opens to admit air at atmospheric pressure to the back side of both diaphragms. This forces the diaphragms forward and causes a piston rod in the booster unit to push the brake master cylinder pistons and apply the service brakes. The amount of atmospheric air admitted to the back side of both diaphragms depends upon the force the driver applies to the brake pedal. The greater the pedal pressure, the more the valve opens. This provides a power boost that multiplies the force applied to the master cylinder pistons in proportion to the pressure on the brake pedal. When the brake pedal is released, the flow of atmospheric air is cut off and inlet manifold vacuum draws off the air behind the diaphgrams. As a result, air pressures within the diaphgram chambers are once again balanced so no power boost is developed. EGR VALVE VACUUM SYSTEM The exhaust gas recirculation (EGR) system allows a small amount of exhaust gas to flow from the exhaust manifold into the inlet manifold when the throttle is opened beyond idle and inlet manifold vacuum is normal. This reduces combustion temperatures in the engine to control oxides of nitrogen emissions. The EGR valve is operated by an integral vacuum actuator that controls a pintle within the valve. The pintle remains closed to prevent exhaust gas recirculation until vacuum is applied to the actuator. The vacuum causes the pintle to open, allowing the measured flow of exhaust gas to enter the inlet manifold. The EGR system used with gasoline engines remains closed during periods of engine idle and deceleration to prevent rough idle from excessive dilution of the air/fuel mixture. It also remains closed at wide-open throttle to prevent power loss. At other times, it rapidly cycles open and closed to modulate the flow of exhaust gas as required. Under certain circumstances, it may remain fully open to provide the maximum EGR. In gasoline engines, the manifold absolute pressure (MAP) sensor measures the strength of inlet manifold vacuum in the EGR vacuum circuit and sends a signal back to the electronic control module (ECM). The ECM uses the signal from the MAP sensor to control fuel delivery and ignition timing. In addition, the ECM will adjust the on-off intervals of the EGR valve to correct the flow of exhaust gas into the cylinders if actual vacuum differs from the preferred vacuum as calculated by the ECM. This provides the required control of oxides of nitrogen emissions while retaining engine performance under all operating conditions. Vacuum for the EGR system of gasoline engines is taken from the throttle body and routed through a hose to the electronic vacuum regulator valve (EVRV). This valve is controlled by the 435 circuit from the ECM. When the EVRV solenoid is energized, the valve routes vacuum to the EGR actuator. The actuator opens the EGR pintle valve to allow exhaust gas to flow into the inlet manifold. When the EVRV solenoid is released, the valve vents the EGR actuator to outside air to close the EGR pintle valve. In the LH6 diesel engine, the operation of the EGR valve is assisted by the exhaust pressure regulator (EPR) valve. At idle, the EPR valve increases exhaust back pressure to force more exhaust through the EGR valve and reduce combustion temperatures. The vacuum which operates the EGR valve and the EPR valve is supplied by an engine-driven vacuum pump. The electronic control module (ECM) controls the EGR valve solenoid to regulate the vacuum to the EGR valve in the same way as with a gasoline engine. The ECM calculates the amount of exhaust gas recirculation based on inputs from the engine speed sensor and the throttle position sensor, and pulses the EGR valve solenoid to control EGR. The manifold absolute pressure (MAP) sensor monitors the control of exhaust gas recirculation as indicated by the air pressure in the EPR vacuum line. If actual vacuum differs from the preferred vacuum as calculated by the ECM, the ECM will adjust the on-off intervals of the EGR valve to correct the flow of exhaust gas into the cylinders. When the ECM recognizes the operating range in which no exhaust gas recirculation is needed, the EGR vent solenoid opens to vent the vacuum at the EGR valve. At idle, the ECM energizes the EPR valve solenoid to send vacuum to close the EPR valve. This increases exhaust back pressure to force more exhaust gas through the EGR system and lower combustion temperatures to reduce oxides of nitrogen emissions. PRELIMINARY CHECKS: POWER BRAKE BOOSTER VACUUM SYSTEM Little or no power assist upon brake application can be caused by a faulty power brake booster vacuum system. A simple two-step procedure can be used to check out the vacuum system if a visual inspection fails to uncover the cause. • With the engine off, apply and release the brake a number of times to exhaust all vacuum from the power brake booster. As many as 8 to 10 strokes may be required. Then hold your foot on the brake pedal with a firm pressure (comparable to the pressure required to bring the vehicle to a normal gradual stop). While maintaining a steady pressure, start the engine. If the vacuum system is working properly, you should feel the brake pedal "fall away" slightly under your foot as the engine starts. If there is no power assist, refer to the R/V, G and P Truck Service Manual, Section 5A-1. • With no pressure applied to the brake pedal, shut off the engine and allow the vehicle to stand undisturbed for 3-5 minutes. Then depress and release the brake pedal a number of times until firm resistance is met with very little brake pedal travel. A vacuum leak or a faulty check valve at the booster unit end of the vacuum hose is indicated if firm resistance is encountered with very little brake pedal travel on the first few strokes. EGR VALVE VACUUM SYSTEM A leak in the EGR (exhaust gas recirculation) vacuum system can upset the ECM’s programmed control of exhaust gas recirculation and adversely affect engine operation. Too much exhaust gas recirculation at idle or cruise with a gasoline engine can result in the engine stalling after closed throttle deceleration, surging during steady throttle cruising, or a rough idle. Too little exhaust gas flow allows combustion temperatures to become too high and bring about detonation ("spark knock") or an overheated engine. In addition, nitrous oxide emissions may be high enough to cause the vehicle to fail an emissions test. Because the source of an EGR system symptom might be traced to a mechanical or electrical condition as well as a faulty vacuum system, an effective systematic diagnosis procedure should examine all three categories of components - not just the vacuum system alone. Therefore, no exclusive vacuum system diagnosis procedures are provided here. For more information on the EGR system, refer to the "Fuel and Emissions Service Manual." VACUUM SYSTEM A-163 A-164 VACUUM HOSE ROUTING CRUISE CONTROL AIR CONDITIONING AUXILIARY HEATER (SEE PAGES 94, 99, 124) VACUUM PUMP I538-.8 DK GRN I ECM (SEE PAGE 65) EPR VALVE SOLENOID = 3 VENT EGR VALVE SOLENOID BRAKE PEDAL DIAGNOSTIC CONNECTOR (SEE PAGE 65) EGR VENT VALVE SOLENOID ENGINE GROUND G115 POWER BRAKE BOOSTER VACUUM SYSTEM EGR VALVE VACUUM SYSTEM (GASOLINE ENGINE) MAP SENSOR EPR VALVE ACTUATOR EGR/EPR VACUUM SYSTEM (DIESEL ENGINE) VACUUM HOSE ROUTING A-165 C187 FRONT OF VEHICLE GT105 S112 12C10 Figure 1 - Daytime Running Lamps Relay C100 1. Battery Junction Block 2. Windshield Washer Motor and Reservoir LH High-Low Headlamp 4. LH High Beam Headlamp 5. LH Park and Turn Lamp 6. LH Front Side Marker Lamp 7. RH High Beam Headlamp 8. RH High-low Headlamp 9. RH Front Side Marker Lamp 10. RH Park and Turn Lamp G105 FRONT ^ OF V E H IC L E ^ S111 GT105 C140 \ \ ^ C137 C139 VIEW FRONT OF VEHICLE 12H2 G105 G106 C149 FRONT ^ OF VEHICLE S112 FRONT OF VEHICLE C154 C155 C150 S111 1. 2. 3. 4. 5. 6. 7. S113' Battery Junction Block LH High-Low Headlamp LH Park and Turn Lamp LH Front Side Marker Lamp RH High-Low Headlamp RH Front Side Marker Lamp RH Park and Turn Lamp C145 C146 FRONT OF VEHICLE 12H1 Figure 2 - Front Headlamps-Base A-166 COMPONENT LOCATOR VIEWS V )E W B C157 C153VIEW A I C151 r i _9 C152 Figure 3 - Front Headlamps-Dual Headlamps-Quad Halogen G107 S212 S209 1. 2. 3. 4. 5. 6. Clutch Switch Dimmer Switch Backup Lamp Switch Ignition Switch Steering Column Turn Signal Switch C286 S210 S207 C100 FRONT OF VEHICLE FRONT OF VEHICLE 1. 2. 3. 4. 5. GT105 I/P Cluster Headlamp Switch Parking Brake Switch Turn Signal Flasher Fuse Block 12H37.2 12H37.1 V FRONT OF VEHICLE C206 VIEW A VIEW B Figure 4 - Headlamp Switch and Fuse Block Figure 6 - l/P Ground COMPONENT LOCATOR VIEWS A-167 1. 2. 3. 4. 5. 6. C424 (INSIDE HARNESS WRAP) LH Rear Marker Lamp RH Rear Backup Lamp RH Rear Taillamp LH Rear Taillamp LH Rear Marker Lamp LH Rear Backup Lamp FRONT OF VEHICLE G403 (LH SIDE) G402 (RH SIDE) C413 FRONT OF VEHICLE C300 S410 >C423 (INSIDE HARNESS WRAP) 12H73.73.1 Figure 9 - Rear Lamps-Fleetside Figure 7 - Rear Lamps Wiring Extension Harness C428 1. 2. 3. 4. 5. 6. 7. C413 C417 (LH SIDE) C415 (RH SIDE) 1. LH Front Clearance Lamp 2. LH Rear Clearance Lamp (LH shown, RH same) RH Rear Taillamp RH Rear Backup Lamp License Lamp LH Rear Backup Lamp LH Rear Marker Lamp LH Rear Taillamp RH Rear Marker Lamp FRONT OF VEHICLE 'GT400 (LH) 12H101 Figure 8 - Rear Lamps-Suburban and Utility A-168 COMPONENT LOCATOR VIEWS 12H100 Figure 10 - Side Clearance Lamps-Dual Rear Wheels VIEW 1. Stoplamp Switch with Cruise Control 2, Stoplamp Switch * FRONT OF VEHICLE VIEW B FigureJ 3 - Stop Lamp Switch Figure 11 - Rear Lamps - Stepside A Figure 12 - Endgate Identification Lamps Figure 14 - Convenience Center COMPONENT LOCATOR VIEWS A-169 "C239 VIEW |~A~| FRONT OF VEHICLE ^ FRONT ^ C OF VEHICLE VEHICLE VIEW B 1. 2. 3. 4. Right Roof Marker Lamp Front Roof Identification Lamps Left Roof Marker Lamp Headlamp Switch 12H106 Figure 15 - Roof Marker Lamps 1. LH Battery 2. RH Battery Figure 16 - Rear Lamps Extension Harness A-170 COMPONENT LOCATOR VIEWS Figure 18 - Batteries - 6.2L V8 and 6.2L V8 HD Engines C200 C106 FRONT OF VEHICLE 1. Generator 2. Starter Motor 3. Starter Motor Solenoid 12H12 Figure 19 - Generator and Starter Motor ■ 5.7L and 7.4L Engines Figure 21 - Battery - 5.7L and 7.4L Engines COMPONENT LOCATOR VIEWS A-171 C196 3 C171 ^ 1 9 ill 1 * HI FRONT OF VEHICLE C135 VIEW C167 C106 FRONT ^ OF VEHICLE FRONT OF V E H IC L E ^ ^ C198 C134 S107 12H19 VIEW B G110 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Water in Fuel Sensor Cold Advance Control Solenoid Fast Idle Solenoid Fuel Shut Off Solenoid Coolant Temperature Switch Throttle Position Sensor Starter Motor Cold Advance/Fast Idle Temperature Switch Fuel Heater Starter Motor Solenoid Manifold Absolute Pressure Sensor Generator S103 VIEW C Figure 22 - Engine Wiring, Right Side - 6.2L and 6.2L HD V8 Engines A-172 COMPONENT LOCATOR VIEWS VIEW D C200 GT102 FRONT OF VEHICLE 11 10 FRONT OF V E H I C L E ^ G110 ^ FRONT ^ O F VEHICLE VIEW |~A] 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Electronic Control Module Idle Air Control Actuator Fuel Injector 2 Fuel Injector 1 Throttle Position Sensor Coolant Temperature Sensor Generator EVRV Solenoid Idle Air Control Actuator Knock Sensor Auxiliary Cooling Fan Temperature Switch Starter Motor Solenoid 1. Engine Temperature Sender 2. Fuel Pump Oil Pressure Switch 3. Generator G115 12H16.4 Figure 23 - Engine Wiring, Right Side - 7.4L Engine FRONT OF VEHICLE VIEW B 12H15 Figure 24 - Engine Wiring, Left Side - 7.4L Engine (Fleetside) COMPONENT LOCATOR VIEWS A-173 C106 C134 C217 GT102 S101 C200 G115 C124 C216 C148 FRONT OF VEHICLE S117 C170 C115 C136 1. 2. 3. 4. 5. 6. 7. 8. 9. Electronic Control Module Idle Air Control Actuator Fuel Injector 2 Fuel Injector 1 Throttle Position Sensor Knock Sensor EGR Solenoid Auxiliary Cooling Fan Temperature Switch Fuel Pump Relay C159 FRONT OF VEHICLE 1. 2. 3. 4. 5. 6. Generator Coil Distributor Electronic Spark Timing Module Fuel Pump Oil Pressure Switch Oxygen Sensor 12H14.2 Figure 25 - Engine Wiring, Right Side - 5.7L Engine A-174 COMPONENT LOCATOR VIEWS 12H14 Figure 26 - Engine Wiring, Rear Left Side - 5.7L Engine (Suburban Utility) C200 GT101 C216 FRONT OF V E H IC L E ^ ^ 1. Electronic Control Module 12H21 Figure 29 - Electronic Control Module - LH6 1. 2. 3. 4. 5. 6. 7. EPR Valve EGR Valve EGR Dump Valve Water Temperature Sender Glow Plug Controller Oil Pressure Sensor Cold Advance Glow Plug Inhibit Relay 5197 5198 5199 C168C104A C136 C107A FRONT J r OF VEHICLE ^ FRONT OF VEHICLE 1. 2. 3. 4. 5. 6. Transmission Transfer Case VSS Output Speed Sensor Oxygen Sensor Input Speed Sensor 12H8.2 Figure 28 - Diesel Engine Harness - LH Side Figure 30 - MT1 Electronically Controlled Transmission COMPONENT LOCATOR VIEWS A-175 FRONT ^ OF VEHICLE C106A 1. Auxiliary Fuel Tank Selector Switch 2. Fuse Block 3. Bus Bar Ground 4. Grommet 105 FRONT OF VEHICLE Figure 33 - Auxiliary Fuel Tank Selector Switch C170 C409 1. Auxiliary Fan Temperature Switch G409 Figure 31 - Auxiliary Cooling Fan Wiring Harness FRONT ^ OF VEHICLE C100 12H34 FRONT OF VEHICLE 1. Battery Junction Block 2. Auxiliary Cooling Fan Relay 3. Auxiliary Cooling Fan C191 Figure 32 - Auxiliary Cooling Fan A-176 COMPONENT LOCATOR VIEWS 1. 2. 3. 4. 5. LH Fuel Tank (Production) LH Fuel Sender Assembly RH Fuel Sender Assembly RH Fuel Tank (Auxiliary) Fuel Tank Selector Valve and Motor Switch Figure 34 - Auxiliary Fuel Tanks - Diesel FRONT OF VEHICLE VIEW A G409 G410 C305 A + fFRONT ro n t « O F VEHICLE 1. LH Fuel Sender and Pump Assembly 2. LH Fuel Tank (Production) 3. RH Fuel Sender and Pump Assembly 4. RH Fuel Tank (Auxiliary) 5. Fuel Tank Selector Valve and Motor Switch VIEW FRONT OF VEHICLE \ Figure 35 - Auxiliary Fuel Tanks - Gasoline C130 C200 FRONT OF V E H IC L E ^ ^ C216 1. Electronic Control Module 2. MAP Sensor 3. Idle Air Control Actuator 4. Fuel Injectors 5. Throttle Position Sensor 6. Coolant Temperature Sensor 7. ESC Knock Sensor 8. ESC Hybrid Function 9. EVRV Solenoid 10. Fuel Pump Relay 9 8 C159 7 S119 Figure 36 - Electronic Engine Controls, RH Side - 5.7L Engine 1. Transmission Converter Clutch Solenoid 2. Vehicle Speed Sensor Figure 38 - Automatic 4-Speed Transmission Wiring COMPONENT LOCATOR VIEWS A-177 C131 C129 C189 C107 C100 12H15 C115 C103 > FRONT OF VEHICLE 1. 2. 3. 4. 5. 6. 7. 8. Electronic Control Module Fuel Pump Relay Manifold Absolute Pressure Sensor Idle Air Control Actuator Fuel Injectors Throttle Position Sensor ESC Knock Sensor ESC Hybrid Function 1. 2. 3. 4. 5. 6. 12H14.2 Figure 39 - Electronic Engine Controls, RH Side - 7.4L Engine A-178 COMPONENT LOCATOR VIEWS EVRV Solenoid Windshield Wiper Motor Fuel Pump Oil Pressure Switch Coolant Temperature Sensor Rear Wheel Antilock Controller Module Brake Pressure Warning Switch S145 VIEW A Figure 40 - Electronic Engine Controls, LH Side - 7.4L C218 C289 1. 2. 3. 4. Heater A/C Control Assembly Lamp Digital Ratio Adapter Controller Module Courtesy Lamp Cigarette Lighter 12H37 Figure 41 - Digital Ratio Adapter Controller Module COMPONENT LOCATOR VIEWS A179 1. Fuse Block 2. Selector Control 3. Blower Switch - Front VIEW [ a ] Figure 44 - A/C and Heater Control Wiring ■ Front 3. Fuse Block 12H61.1 Figure 45 - A/C Control Wiring - Rear A-180 COMPONENT LOCATOR VIEWS Figure 47 - Rear Heater Switch Wiring FRONT ^ OF VEHICLE C426 C312 GT402 C425 1. Rear Blower Motor 2. Rear Resistors VIEW [ a ] 12H61.3 Figure 48 - Rear Heater Blower Wiring C222 C223 1. 2. 3. 4. 5. Glow Plugs Wait Lamp Water in Fuel Indicator Check Engine Lamp Driver Module Low Coolant Warning Module Instrument Center FRONT * OF VEHICLE FRONT * OF VEHICLE VIEW A FRONT w OF VEHICLE VIEW [ a ] C225 FRONT OF VEHICLE 1. Safety Belt Retractor Switch C306 Figure 49 - l/P Wiring - 6.2L V8 and 6.2L V8 HD Engine Figure 50 - Safety Belt Retractor Switch Wiring COMPONENT LOCATOR VIEWS A-181 r n 1. 2. 3. 4. 5. C246 1 C166 Four-Wheel Drive Indicator Lamp Transfer Case Switch Four-Wheel Drive Shift Lever Lamp Diode Assembly Fuse Block 2. Transfer Case Switch OF V E H IC L E ^ 12H121.1 Figure 52 - Transfer Case Wiring - V300 12H122 C224 FRONT OF VEHICLE v ie w Figure 51 - Transfer Case Wiring - V100, V200 A-182 COMPONENT LOCATOR VIEWS Pb ] Figure 53 - Transfer Case - Power and Ground Connections C251 FRONT OF VEHICLE FRONT OF VEHICLE 1. 2. 3. 4. 5. 6. Bus Bar Ground Clutch Switch Fuse Block Cruise Control Module Brake Switch DRAC Module GT106 1. 2. 3. 4. 5. G200 Bus Bar Ground Fuse Block Cruise Control Module Brake Switch DRAC Module 12H72 12H72.1 » FRONT OF VEHICLE C250 C252 FRONT OF V E H IC L E ^ ^ ^ FRONT OF VEHICLE VIEW VIEW [ a ] FRONT OF VEHICLE VIEW B VIEW [A~| C256 C244 FRONT OF VEHICLE VIEW C Figure 54 ■ Cruise Control Wiring - Manual Transmission C253 C244 C289 FRONT OF VEHICLE VIEW C Figure 55 - Cruise Control Wiring - Automatic Transmission COMPONENT LOCATOR VIEWS A-183 Figure 56 - Cruise Control Servo - 6.2L and 6.2L V8 HD Engines A-184 COMPONENT LOCATOR VIEWS Figure 57 - Cruise Control Servo - 5.7L and 7.4L Engines Figure 58 - Cruise Control Actuator GT602 C435 1. Glove Box Lamp Switch 2. Fuse Panel OF VEHICLE 12H 1 2 7 12H 123 C438 (RH SIDE) C437 (LH SIDE) 2 (FRONT) 3 (REAR) VIEW A Figure 59 - Dome Lamp Wiring VIEW B Figure 60 - Front Door Jamb Switch Wiring COMPONENT LOCATOR VIEWS A-185 12H7.1 Figure 61 - Vanity Mirror Switch Wiring Figure 64 - Rear Gate Switch Wiring A-186 COMPONENT LOCATOR VIEWS FRONT OF VEHICLE 1 2H 50 GT601 GT500 FRONT OF VEHICLE 1. 2. 3. 4. 1. Tailgate Window Switch Figure 66 - Tailgate Window Front Wiring Power Door Lock Relay Bus Bar Ground In-Line Auto Fuse Fuse Block VIEW A Figure 67 - Power Window, Locks, and Mirror Wiring COMPONENT LOCATOR VIEWS A-187 FRONT ^ OF V E H IC L E ^ C501 (LH) FRONT OF V E H IC L E -^ C502 (LH) C603 (RH) VIEW A C501 (LH) C602 (RH) FRONT OF VEHICLE ^ 1. Rear Panel Door Lock Actuator 2. Contact Assembly VIEW [ a ] VIEW B 1. Power Door Lock Actuator 2. Power Door Lock Switch FRONT OF V E H IC L E ^ 12H54 VIEW TYPICAL Figure 70 - Power Door Lock Wiring Figure 68 - Rear Panel Door Lock Wiring C500 (LH-2 DOOR) C506 (LH-4 DOOR) 0603 (RH) 12H52.2 FRONT OF VEHICLE C700 (LH) C800 (RH) C508 (LH) :C600 (RH) % ^ -C 5 0 9 FRONT C501 (LH) C602 (RH) 0503 (LH) 0604 (RH) 1. 2. 3. 4. Power Mirror Switch Power Window Motor Power Door Lock Actuator Power Window Switch VIEW [ a ] TYPICAL Figure 69 - Front Door Wiring with Power Door Locks, Windows and Mirrors A-188 COMPONENT LOCATOR VIEWS 12H56 Figure 71 - Rear Door Power Windows and Locks C904 C904 S908 — , FRONT ^ OF VEHICLE FRONT OF VEHICLE S908 12H121 C904 C447 1. Tailgate Window Motor 2. Cut-Out Switch 3. Tailgate Window Switch, Key Operated FRONT * OF VEHICLE FRONT OF VEHICLE 1. Rear Tailgate Window Motor 2. Tailgate Window Switch, Key Operated 3. Cut-Out Switch VIEW [A] C448 C905 G904 G401 C405 FRONT ^ OF #▼ VEHICLE FRONT ^ OF VEHICLE C406 VIEW [ a ] Figure 72 - Tailgate Rear Window Wiring - Utility VIEW B VIEW B J T q FRONT F VEHICLE C905 VIEW C Figure 73 - Tailgate Rear Window Wiring - Suburban COMPONENT LOCATOR VIEWS A-189 FRONT OF VEHICLE C214 1. Pulse Wiper Module Wiring Figure - 78 Pulse Wiper Module Wiring C118 1. Backup Lamp Switch 2. Vehicle Speed Sensor FRONT OF VEHICLE C141 Figure 79 - Backup Lamp Switch - Manual Transmission 1. RH License Lamp 2. LH License Lamp 12H104 Figure 80 - License Lamps Wiring - Fleetside COMPONENT LOCATOR VIEWS A-191 FRONT OF VEHICLE C300B FRONT OF VEHICLE S118 FRONT OF VEHICLE G109 GT 105 1. Auxiliary Battery Junction Block 2. Auxiliary Battery Relay 3. Auxiliary Battery 12H116 VIEW FRONT ^ OF VEHICLE Figure 85 - Auxiliary Battery Figure 83 - Camper and Trailer Wiring - Utility C300B 12H117.1 Figure 84 - Camper and Trailer Wiring - Fleetside A-192 COMPONENT LOCATOR VIEWS Figure 86 - Radio Wiring, Front Harness VIEW |~A~l COMPONENT LOCATION A/C Compressor ................................... A/C Diode ............................................... Automatic Transmission Backup Lamp Switch ........................ Auxiliary B attery...................................... Auxiliary Battery Relay, LH side ......... Auxiliary Cooling Fan Temperature Switch .......................... Page -- Figure 42 Front of engine.................................................... .............. 179 42 At A/C compressor............................................. .............. 179 Bottom of steering column ............................... .............. 167 LH side of vehicle behind headlam p.............. .............. 192 On inner fender w e ll.......................................... .............. 192 Lower RH side of e n g in e ............................... .............. 173 174 176 Below radiator s u p p o rt...................................... .............. 176 LH inner fender w e ll............................ .............. .............. 176 Auxiliary Cooling F a n ............................ Auxiliary Cooling Fan Relay ................. Auxiliary Fuel Tank Selector Switch .................................................. RH side of d a s h .................................................. .............. 176 On inner fender w e ll........................................... .............. 191 Auxiliary Junction Block, LH side 192 Backup Lamp S w itc h ............................ At top of transmission........................................ .............. 191 Backup Lamp, LH ................................. LH rear of vehicle............................................... .............. 168 168 Backup Lamp, RH ................................. RH rear of vehicle............................................... .............. 168 168 Battery Junction B lo c k .......................... Engine compartment, LH C o w l........................ .............. 166 166 176 179 186 186 Blower M o to r.......................................... RH side of cowl .................................................. .............. 179 Brake Pressure Warning S w itc h ......... Below master cylinder........................................ .............. 178 Brake Switch .......................................... On top of brake pedal assem bly..................... .............. 183 183 .............. 167 Bus Bar G round...................................... LH side of l / P ...................................................... 176 180 182 183 183 187 190 191 Cargo Lamp Switch Upper ................ LH B-Pillar ........................................................................... 187 Check Engine Lamp Driver Module . . . Under l / P ............................................................. ................ 181 Cigarette Lighter ................................... . In ash receptacle ............................................... ................ 179 Clutch Start Switch................................. LH side of steering colum n............................................... 167 Clutch Sw itch.......................................... , On top of clutch pedal assembly ................... ................ 183 Coil ............................................................ Top rear of e n g in e ............................................................. 174 Cold Advance Control Solenoid ......... , Front LH side of engine ................................... ................ 172 Cold Advance Glow Plug Inhibit Relay ...................................................., Engine compartment, LH rear side ................ ................ 175 Cold Advance/Fast Idle Temp Switch . Lower RH rear of engine................................... ................ 172 Combination Lamp, LH Rear .............. . LH rear of vehicle............................................... ................ 169 Combination Lamp, RH Rear .............. . RH rear of vehicle............................................... ................ 169 A-194 COMPONENT LOCATER INDEX 5 85 85 23 25 31 32 32 33 81 85 79 8 9 8 9 2 3 32 42 62 63 43 40 54 55 6 33 47 53 54 55 67 74 81 65 49 41 5 54 26 22 28 22 11 11 COMPONENT LOCATION Convenience C enter................... Coolant Temperature Sender (7.4L G aso lin e)........................ Page -- Figure LH side of l / P ...................................................................... 169 11 Lower LH side of engine................................................... 173 177 178 24 37 40 Top center of engine ........................................................ 173 177 178 Front of engine.................................................................... 172 Coolant Temperature Switch (Diesel) . 173 Below l/P ............................................................................. 179 Courtesy Lamp ...................................... Cruise Control A c tu a to r........................ Part of multi function switch ............................................ 184 Cruise Control M o d u le .......................... Behind l/P, on LH side of steering column ................... 183 183 Cruise Control Servo (5.7L and 7.4L G asoline)................... Rear of e n g in e .................................................................... 184 Cruise Control Servo (6.2L Diesel) . . . Front of en gine.................................................................... 184 Cut-Out Sw itch........................................ Upper RH side of tailgate (Utility) ................................... 189 Cut-Out Sw itch........................................ Upper LH side of tailgate (Suburban) ............................ 189 DRAC Module ........................................ l/P near steering column................................................... 179 183 183 LH front inner fender ........................................................166 DRL R e la y ............ Top rear of e n g in e ............................................................. 174 Distributor ............ Above passenger seats on roof ...................................... 185 Dome Lamp, Front Above rear cargo area on roof ........................................ 185 Dome Lamp, Rear Under LH side of l / P .......................................................... 173 ECM ..................... 174 175 177 178 EGR Dump V a lv e ................................... Top LH side of engine ...................................................... 175 EGR Solenoid ........................................ Top RH side of e n g in e ...................................................... 174 EGR V a lv e ............................................... Top LH side of engine ...................................................... 175 EPR V a lv e ............................................... Top LH side of engine ...................................................... 175 ESC Hybrid Function (5.7L Gasoline) . Top RH side of e n g in e ...................................................... 177 ESC Hybrid Function (7.4L Gasoline) . On RH side of cowl p an el................................................. 178 EVRV Solenoid........................................ Top front of engine............................................................. 173 177 178 Top rear of e n g in e ............................................................ 174 Electronic Spark Timing M o d u le ......... Engine Speed Sensor .......................... Top RH side of e n g in e ...................................................... 172 Evaporator Pressure Control Switch . . RH side of cowl ................................................................. 179 Fast Idle Solenoid ................................. On top of engine ............................................................... 172 In l/P cluster........................................................................ 182 Four-Wheel Drive Indicator Lamp Four-Wheel Drive Shift Level Lamp . . . At transfer case shift lever ............................................... 182 Front Blower S w itch ............................... Center of l / P ........................................................................ 180 Front Resistor B lock............................... RH side of cowl panel........................................................ 179 Fuel Heater ............................................. Engine compartment, on cowl behind e n g in e .............. 172 23 36 40 22 23 41 58 54 55 Coolant Temperature Sensor (5.7L and 7.4L Gasoline) . 57 56 72 73 41 54 55 1 26 59 59 23 25 29 36 39 28 25 28 28 36 39 23 36 40 26 22 43 22 51 51 44 43 22 COMPONENT LOCATION Page -- Figure ___ 173 23 Fuel Injector . . ..................................... . Top center of engine ............................................... 173 24 174 25 177 36 178 39 Fuel Pump Oil Pressure Switch 26 (5.7L G asolin e)................................ . Top rear of e n g in e .................................................... . . . . 174 Fuel Pump Oil Pressure Switch 24 (7.4L G aso lin e)................................. . Lower LH side of engine........................................... . . . . 173 178 40 23 Fuel Pump R e la y ................................ . Engine compartment on cowl behind engine . . . ___ 173 174 25 177 36 178 39 27 ___ 175 . In fuel ta n k .................................................................. Fuel Pump and Sender Assembly . . . 176 33 177 35 ___ 172 22 . Front LH side of engine .......................................... Fuel Shut Off S olenoid....................... Fuel Tank Selector Valve and Motor 34 Switch ............................................... . RH frame rail near auxiliary fuel ta n k ..................... . . . . 176 177 35 . . . . 167 4 . LH side of l / P ............................................................. Fuse Block............................................ 176 33 180 44 180 45 180 47 182 51 182 53 183 54 183 55 185 60 187 67 64 186 ___ 171 19 . Front of engine........................................................... Generator ............................................ 172 22 173 23 173 24 174 26 ___ 185 60 Glove Box Lamp S w itc h ..................... . In glove box on RH side of l/P ............................... . . . . 175 28 Glow Plug Controller ......................... . Top rear of e n g in e .................................................... 49 Glow Plugs Wait L a m p ....................... . In instrument cluster................................................. ___ 181 . . . . 169 14 Hazard Flasher ................................... . LH side of l/P on convenience c e n te r ................... 5 Headlamp Dimmer Switch ................ . LH side of steering colum n...................................... ___ 167 3 Headlamp, LH High Beam (Quad) . . . LH front of vehicle .................................................... . . . . 166 3 Headlamp, LH Low Beam (Quad) . .. . LH Front of v eh ic le .................................................... . . . . 166 3 Headlamp, Low Beam (Quad) ......... . RH front of vehicle .................................................... ___ 166 3 Headlamp, RH High Beam (Quad) . . . RH Front of vehicle.................................................... . . . . 166 2 . RH front of vehicle .................................................... ___ 166 Headlamp, RH High-Low (Base) 41 Heater A/C Control Assembly Lamp . . Front center of l/P .................................................... . . . . 179 43 High Blower R e la y .............................. . Engine compartment near blower m o to r.............. ___ 179 4 I/P C lu s te r............................................ . LH side of l / P ............................................................. ___ 167 COMPONENT LOCATION Page -- Figure Idle Air Control A ctuator..................... . Top RH side of e n g in e .......................................... ............173 23 174 25 31 176 Ignition S w itc h ...................................... . RH side of steering column................................... ........... 167 5 In-Line Diode (4 W D )............................ . In 4WD harness at RH side of fuse block ......... ........... 182 51 In-Line Fuse (Camper/Trailer Wiring) . . Center of cowl panel in dash conduct................ ........... 191 81 In-Line Fuse (Underhood lamp) (Diesel)............................................... . LH inner fender w e ll............................................... ........... 186 62 In-Line Fuse (Underhood lamp) (Gasoline).......................................... ............186 63 In-line Fuse (TP2 O n ly )........................ . LH side on inner fender w e ll................................. ............191 81 Input Speed S e n s o r............................ . LH side of transmission ........................................ ............175 30 Instrument cluster ............................... . LH side of l / P .......................................................................181 49 Knock Sensor ...................................... . Lower RH side of engine ................................................. 173 23 174 25 178 39 184 56 LH B a tte ry ............................................. . Engine Compartment, front LH side ...............................170 18 LH H o rn ................................................. . LH front of vehicle ................................................. ............170 17 LH License L a m p ................................. . Rear center of vehicle............................................ ............191 80 LH Rear Door Jamb Switch .............. 59 ........... 185 LH Rear Side Marker Lamp .............. ........... 168 8 9 168 License Lamp ...................................... . Rear center of vehicle........................................................ 168 8 Light S w itch.......................................... . LH side of l / P ........................................................... ......... 167 4 170 15 Low Coolant Warning M odule............ . Behind LH side of l/P ............................................ ............181 49 MAP S ensor.......................................... . Top RH rear of engine .......................................... ............172 22 177 36 178 39 Multi Function S w itc h .......................... . On steering column ............................................... ........... 184 58 Oil Pressure Sensor (Diesel).............. ........... 175 28 Output Speed Sensor ....................... . LH side of transmission ........................................ ......... 175 30 Oxygen Sensor ................................... . LH exhaust manifold............................................... ......... 174 26 175 30 Powertrain Control Module (PCM) . . . . Under LH side of l / P .......................................................... 173 23 Panel Door C ontractor....................... ........... 188 68 Park Brake Warning Switch .............. . Under LH side of l / P .......................................................... 167 4 Park and Turn Lamp, LH (Base) . . . . . LH front of vehicle ................................................. ........... 166 2 Park and Turn Lamp, LH (Quad) . . . . LH front of vehicle ................................................. ........... 166 3 Park and Turn Lamp, RH (Base) . . . . . RH front of vehicle ................................................. ......... 166 2 Park and Turn Lamp, RH (Quad) . . . . RH front of vehicle ................................................. ......... 166 3 Power Door Lock A c tu a to r................ ........... 188 69 Power Door Lock A c tu a to r................ . RH front d o o r .......................................................... ........... 188 70 Power Door Lock A c tu a to r................ . Rear side d o o r s ................................................................. 188 71 Power Door Lock Relay ..................... . At RH side of steering column s u p p o rt.............. ........... 187 67 Power Door Lock Switch ................... . Upper RH front d o o r.......................................................... 188 70 Power Mirror S w itch ............................ . Upper LH front d o o r .......................................................... 188 69 Power Window M o to r.......................... . Lower LH front d o o r ............................................... ......... 188 69 Power Window M o to r.......................... . Rear side d o o r s ...................................................... ......... 188 71 Power Window Switch ........................ . At LH front d o o r ...................................................... ......... 188 69 69 Power Window M o to r.......................... . Lower LH front d o o r .......................................................... 188 COMPONENT LOCATER INDEX A-195 COMPONENT LOCATION Page -- Figure 78 ....................191 Pulse Wiper M o d u le ............................ . Under LH side of l / P ............................... 18 RH Battery............................................. . Engine compartment, front LH s id e .............. ....................1 7 0 171 RH Fuel Sender A ssem bly................ . RH Fuel T a n k .................................................... ....................1 7 6 17 7 RH RH RH RH Horn ............................................... License Lam p................................. Rear Door Jamb Switch .............. Rear Side Marker Lamp .............. . RH front of vehicle .......................................... . Rear center of vehicle............................ .. . On RH B-pillar ................................................. . RH rear of vehicle............................................. Radio Receiver...................................... . Center of l / P ...................................................... Rear A/C Blower M otor....................... Rear A/C Blower S w itc h ..................... Rear A/C and Heater Controls ......... Rear Gate S w itch ................................. Rear Heater Blower Motor ................ Rear Heater Blower Resistors............ Rear Panel Door Lock Actuator Rear Resistor Block ........................... Rear Wheel Antilock ........................... Controller Module Rear Window Defogger S w itch ......... Roof Identification L am p s................... Roof Marker Lamp, L H ....................... Roof Marker Lamp, R H ....................... Safety Belt Retractor S w itc h .............. Selector Control ................................. Side Marker Lamp, LH Front (Base)................................................. Side Marker Lamp, LH Front (Base)................................................. Side Marker Lamp, LH Front (Quad) ............................................... Side Marker Lamp, RH Front (Quad) ............................................... Speaker, F ro n t...................................... Speaker, Left Front.............................. Speaker, Left R e a r ............................... Speaker, Right Front .......................... Speaker, Right R e a r............................ Starter Motor U n d e r............................ Starter Motor L o w e r .......................... Starter Motor S olenoid....................... Starter Motor S olenoid....................... Stop Lamp Switch .............................. Tailgate Window Motor (Utility) ......... Tailgate Window Motor (Suburban) Tailgate Window Switch (Key O p erated)................................. 21 34 35 ....................1 7 0 ....................191 17 80 ....................185 ....................168 168 ....................192 193 ....................1 8 0 ....................180 ....................1 8 0 ....................186 ....................181 ................181 59 8 9 86 87 46 . . . . . . . . . Top rear of v e h ic le .......................................... Center of l / P ...................................................... Center of l / P .......................................... .. RH rear of vehicle............................................. Rear LH side of vehicle................................... At rear heater blower motor ........................ At rear d o o r ................................................... ....................1 8 8 RH side of engine com partm ent .................. ....................1 8 0 LH side of master cylinder ............................ ....................1 7 8 . . . . . . Center of l / P ...................................................... Front top of ro o f............................................... Front top LH side of roof ............................... Front top RH side of roof ............................... At safety belt assembly................................... Center of l / P ................................................... ....................190 ....................170 ....................1 70 74 15 15 ....................1 70 ....................181 ....................180 15 50 44 . Front LH side of vehicle ................................. ....................166 2 . Front RH side of v e h ic le ................................. ....................166 2 . Front LH side of vehicle ................................. ....................166 3 . . . . . . . . . . ....................166 ................193 ....................1 93 ................... 193 3 87 87 Front RH side of v e h ic le ................................. Top center of l/P .......................................... LH side of l / P .................................................... LH rear side of vehicle ................................... RH side of l / P .................................................... RH side of vehicle .......................................... RH side of engine............................................. RH side of engine .......................................... Under RH side of engine ............................... Lower RH side of engine .............................. . Above brake pedal ...................................... . RH center of tailgate ...................................... . LH center of ta ilg ate ...................................... ................... 193 ....................193 ................... 171 ................... 172 ................... 171 ................... 1 7 3 ............... 1 6 9 ................... 189 ................... 1 8 9 . Center of tailgate ............................................. ................1 89 189 A-196 COMPONENT LOCATER INDEX 47 45 64 48 48 68 45 40 87 87 87 19 22 19 23 13 72 73 72 73 Page -- Figure COMPONENT LOCATION 8 Taillamp, L H ........................................ . . Rear LH side of vehicle................................................. . . 168 168 9 8 Taillamp, RH ...................................... . . Rear RH side of vehicle .............................................. . . 168 168 9 22 Throttle Position Sensor (Diesel) . . . . . Front RH side of e n g in e .............................................. . . 171 74 Timer R e la y ........................................ . . Below fuse block .......................................................... . . 190 51 Transfer Case S w itch ........................ . . Top of transfer c a s e ..................................................... . . 182 Transmission Converter Clutch 38 Solenoid.......................................... . . LH rear of transmission................................................. . . 177 4 Turn Signal Flasher .......................... . . LH side of l/P, on fuse block........................................ . . 167 5 Turn Signal S w itch ............................ . . LH side of steering colum n.......................................... . . 167 63 Underhood Lamp (Gasoline) ......... . . RH side of cowl ............................................................ . . 186 62 Underhood Lamp (Diesel) .............. . . LH inner fender w e l l ..................................................... . . 186 30 Vehicle Speed S e n s o r ..................... . . Rear of transfer case (4WD) ........................................ . . 175 38 Vehicle Speed Sensor ..................... . . Rear of transmission (2WD) ........................................ . . 177 191 79 3 Washer Motor ................................... . . Engine compartment, LH fe n d e r................................. . . 166 28 Water Temperature Sender ............ . . Front LH side of engine .............................................. . . 175 49 Water in Fuel Indicator..................... . . In instrument cluster..................................................... . . 181 22 Water in Fuel S e n s o r........................ . . Engine compartment on cowl behind engine ......... . . 172 40 Windshield Wiper M o to r................... . . Top LH side of c o w l..................................................... . . 178 Connectors: 2 C100 ............................................... . . Engine compartment, LH cowl ................................... . . 162 166 3 186 63 167 4 168 7 175 28 176 31 62 C100A ............................................. . . In engine compartment at LH inner fender well . . . . . . 186 186 63 62 C101A ............................................. . . At underhood lam p....................................................... . . 186 . . 178 40 C103 ............................................... . . At rear wheel anti-lock controller module................... 74 C103A ............................................. . . In lower LH side of engine compartment near cowl . . . 190 . . 178 40 C104 ............................................... . . At brake pressure warning switch.............................. 30 C104A ............................................. . . At top center of transmission ..................................... . . 175 30 C105 ............................................... . . At output speed sensor .............................................. . . 175 19 C106 ............................................... . . Front of engine at generator....................................... . . 171 172 22 174 26 33 C106A ............................................. . . At cowl, above steering column ................................. . . 176 22 C107 ............................................... . . At coolant temperature sensor ................................... . . 172 173 23 177 36 177 37 178 40 22 C107 ............................................... . . At coolant temperature switch..................................... . . 172 28 C108 ............................................... . . At cold advance glow plug inhibit re la y ..................... . . 175 26 C109 ................................................ . . At coil ............................................................................. . . 174 . . 172 22 C110 ............................................... 22 . , . At glow plug # 4 ............................................................ . . 172 . . 172 22 C112 ............................................... cm .............................. COMPONENT LOCATION C113 ........................................ C114 ........................................ C115 ........................................ C118 C120 C121 C122 C123 C124 C125 C126 C127 C128 C129 C130 C131 C132 C133 C134 C134 C135 C136 C137 C138 C139 C140 C141 C142 C143 C144 C145 C146 . . . . Page -- Figure At glow plug # 8 .................................................................. 172 22 Top of engine near c o il...................................................... 174 26 At fuel pump oil pressure sw itch...................................... 173 24 174 26 175 28 178 40 At backup lamp s w itch ...................................................... 191 79 At glow plug #1 .................................................................. 175 28 At glow plug # 3 .................................................................. 175 28 At glow plug # 5 .................................................................. 175 28 At glow plug # 7 .................................................................. 175 28 At electronic spark timing m odule.................................... 174 26 Engine compartment, near LH front of cowl .................166 2 166 3 167 4 LH inner fender, at daytime running lamp re la y ............166 1 In engine compartment at LH side of cowl ................... 187 66 In engine compartment at LH side of cowl ................... 187 66 At fuel injector 1 .................................................................. 173 23 174 25 177 36 178 39 At fuel injector 2 .................................................................. 173 23 174 25 177 36 178 39 At EVRV solenoid................................................................169 13 177 36 178 40 At ESC hybrid function...................................................... 177 36 178 39 At LH side of cowl p a n e l.................................................... 177 37 At TP sensor ....................................................................... 172 22 At throttle position sensor.................................................. 173 23 174 25 177 36 178 39 At map s e n s o r.................................................................... 172 22 177 36 178 39 At top center of transmission ........................................... 174 26 175 30 Front LH side marker la m p ............................................... 166 2 Front LH high-low headlam p.............................................166 2 Front LH park lamp ...........................................................166 2 Front LH turn la m p ............................................................. 166 2 At vehicle speed s e n s o r....................................................191 79 At LH h o r n ........................................................................... 170 17 At RH h o rn ........................................................................... 170 17 Front RH high-low headlamp .......................................... 166 2 Front RH side marker la m p ............................................... 166 2 Front park la m p .................................................................. 166 2 COMPONENT LOCATION C147 C148 C149 C150 C151 C152 C153 C154 C155 C156 C157 C159 C161 C162 C163 C165 C166 C166 C167 C168 C169 C170 C171 C172 C173 C174 C175 C177 C178 C179 C180 C181 C184 C185 C187 C188 C189 Page -- Figure ............................................... . . Front RH turn la m p ........................................................ . . 166 2 ............................................... . . At fuel pump relay ........................................................ . . 173 23 174 25 177 36 178 39 (Q u a d )................................... . . Front LH low beam headlam p...................................... . . 166 3 (Q u a d )................................... . . Front LH high beam h ead lam p ................................... . . 166 3 (Q u a d )................................... . . Front LH turn la m p ........................................................ . . 166 3 (Q u a d )................................... . . Front LH park lamp ...................................................... . . 166 3 (Q u ad )................................... . . Front LH side marker la m p .......................................... . . 166 3 relay.................................................................................. . . 167 4 (Q u a d )................................... . . Front RH low beam headlamp ................................... . . 166 3 (Q u a d )................................... . . Front RH high beam headlam p................................... . . 166 3 (Q u a d )................................... . . Front RH turn la m p ........................................................ . . 166 3 (Q u a d )................................... . . Front RH park lamp ...................................................... . . 166 3 ............................................... . . At knock s en s o r............................................................. . . 173 23 174 25 177 36 178 39 ............................................... . . At idle air control actuator............................................. . . 173 23 174 25 177 36 178 39 ............................................... . . Engine compartment, near battery junction block . , . . 179 42 ............................................... . . At engine temperature sender ................................... . . 173 24 175 28 ............................................... . . At A/C compressor........................................................ . . 179 42 ............................................... . . At clutch switch ............................................................. . . 183 54 ............................................... . . Near steering colum n.................................................... . . 183 55 ............................................... . . At cold advance control solenoid .............................. . . . 172 22 ............................................... . . At glow plug controller................................................. . . . 175 28 ............................................... . . At transmission converter clutch solen oid................ . . 177 38 ............................................... . . At auxiliary cooling fan temperature s w itc h .............. . . 173 23 174 25 176 31 ............................................... . . At fast idle solenoid ...................................................... . . 172 22 ............................................... . . At rear LH side of transmission................................... . . 175 30 ............................................... . . At input speed sensor ................................................. . . . 175 30 ............................................... . . At EGR valve .................................................................. . . 175 28 ............................................... . . At engine speed s e n s o r............................................... . . 172 22 ............................................... . . At high blower r e la y ...................................................... . . . 179 43 ............................................... . . At evaporator pressure control sw itch ....................... . . 179 43 ............................................... . . At front resistor b lo c k ...................................................., . . 179 43 ............................................... . . At front blower motor ...................................................., . . 179 43 ............................................... . . At rear resistor block ..................................................... . . 180 45 ............................................... . . At cruise control servo ................................................. . . . 184 56 184 57 ............................................... . . In cruise harness near servo........................................, . . 184 56 184 57 3 ............................................... . . At windshield washer bottle ......................................... . . 184 , . . 178 40 ............................................... . . At windshield wiper m otor............................................ 40 ............................................... . . At windshield wiper m otor............................................ . . . 178 COMPONENT LOCATER INDEX A-197 COMPONENT LOCATION C190 ........................................ C191 ........................................ C192 ........................................ C193 ........................................ C194 ........................................ C195 ........................................ C196 ........................................ C197 ........................................ C198 ........................................ C199 ........................................ C200 ........................................ Page -- Figure At auxiliary cooling fan re la y ................................... At auxiliary cooling f a n ............................................. Engine compartment, LH side near c o w l.............. At EGR dump valve . ............................................. At EPR valve ............................................................. At EGR solenoid......................................................... At fuel h e a te r............................................................. At water in fuel sensor ............................................. At cold advance/fast idle temperature switch At fuel shut off solenoid ........................................... Under l/P near ECM /PCM /TCM ............................... C202 At light switch............................................................. C203 C204 C207 C208 C212 C214 C215 LH side of l / P ............................................................. At radio ....................................................................... At pulse wiper module ............................................. Near fuse block ......................................................... Under LH side of l/P near fuse block..................... At pulse wiper module ............................................. Under l/P at ECM /PCM /TCM ................................... C216 Under l/P at ECM /PCM /TCM ................................... C217 C218 Under l/P near ECM /PCM /TCM ............................... At courtesy lamp ...................................................... C219 C220 C221 C222 C223 C224 C225 C226 C227 C228 C229 C230 At fuse block ............................................................. At l/P courtesy la m p .................................................. At heater A/C control assembly lamp ................... At glow plugs wait la m p .......................................... At water in fuel indicator........................................... At fuse block ............................................................. At low coolant warning m odule............................... At transfer case s w itch ............................................. At LH front door jamb switch ................................. At Lh front door jamb sw itch................................... At RH front door jamb switch ................................. At glove box lamp switch ........................................ A-198 COMPONENT LOCATER INDEX . . . . 176 ___ 176 ___ 176 ___ 175 ___ 175 ___ 174 ___ 172 ___ 172 ___ 172 ___ 172 ___ 171 173 174 175 177 178 ___ 167 170 192 . . . . 167 ___ 192 ___ 191 ___ 185 ___ 190 ___ 191 ___ 171 173 174 175 177 178 . . . . 171 173 174 175 177 178 . . . . 174 ___ 179 185 ___ 185 ___ 185 ___ 179 ___ 181 . . . . 181 ___ 182 ___ 181 ___ 182 . . . . 185 . . . . 185 ___ 185 . . . . 185 32 32 32 28 28 25 22 22 22 22 19 23 25 29 36 39 4 15 86 4 86 78 60 74 78 19 23 25 29 36 39 19 23 25 29 36 39 25 41 60 60 60 41 49 49 53 49 52 60 60 60 60 COMPONENT LOCATION Page - Figure C231 ............................................... C232 ............................................... . . At auxiliary fuel tank selector switch .......................... C233 ............................................... . . At selector control .................. ..................................... C234 ............................................... . . At front blower switch................................................... C235 ............................................... . . l/P harness, near front blower switch ........................ C238 ............................................... . . LH side of l/P, near light switch................................... C239 ............................................... . . At light switch................................................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At At At At radio .......................................................................... radio .......................................................................... LH front speaker ..................................................... front mono-speaker ................................................. .. .. .. .. .. .. .. At At At At At At At 4WD shift lever c a m ................................................. LH front speaker ..................................................... RH front speaker ..................................................... DRAC module .......................................................... brake switch............................................................... cruise control module............................................... brake switch............................................................... . . . . . . . . . . . . . . . . . . . . At DRAC module .......................................................... At fuse block ................................................................. At fuse block ................................................................. At fuse block ................................................................. In engine compartment near LH side of cowl ......... l/P harness, under RH side of l/P .............................. In engine compartment near LH side of cowl ......... At power door lock relay............................................... At power door lock relay.............................................. Near fuse panel ............................................................ l/P harness, under RH side of l/P .............................. In engine compartment near LH side of cowl ......... At tailgate window s w itch ............................................ Under LH side of l/P near fuse block.......................... Under LH side of l/P near fuse block.......................... Under LH side of l/P near fuse block.......................... At rear window defogger switch ................................. In lower LH side of engine compartment near cowl . Under LH side of l/P near fuse block.......................... At A/C heater controls ................................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C282 ............................................... . . RH side of l/P near A-pillar.......................................... C283 ............................................... . . . At fuse block ................................................................. C285 ............................................... . . . At fuse block ................................................................. C288 ............................................... . . . At 4WD indicator la m p ................................................. C289 ............................................... , . . At DRAC module .......................................................... . . . . . . . . . . . . . . . . . . C240 C241 C242 C243 C244 C246 C247 C248 C250 C251 C252 C253 C254 C256 C258 C259 C260 C261 C262 C263 C264 C265 C266 C268 C271 C274 C275 C276 C277 C278 C279 C280 C281 C291 C299 C300 C300 ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... . . . . . . . . . . . ............................................... , . ............................................... , . ............................................... . . ............................................... . . . . . . . . . . . . . . . . . . . . . . . . . . l/P Harness, LH side, at diode assembly................... At cigarette lighter ........................................................ LH side rail at rear crossmember (Utility)................... LH side rail at rear crossmember (Fleetside)............ 176 176 180 180 180 170 170 192 193 192 193 193 183 182 193 193 183 183 183 183 183 183 187 187 187 187 187 187 187 187 187 187 187 187 190 190 190 190 190 190 180 180 180 180 180 182 179 183 167 179 192 192 33 33 44 44 44 15 15 86 87 86 87 87 55 51 87 87 55 55 55 55 55 55 67 67 67 67 67 67 67 67 67 67 67 66 74 74 74 74 74 74 45 47 45 45 47 51 41 55 4 41 83 84 JOMPONENT LOCATION Page -- Figure ............................................... . . Above rear crossmember, towards RH side of veh icle........................................................................... . 168 168 C300 . . < ........................................ . . LH side rail at rear crossmember (Suburban) ............ . 191 C300A ............................................ . . LH side rail at rear crossmember (Utility)..................... . 192 C300A ............................................ . . LH side rail at rear crossmember (Fleetside).............. . 192 C300A ............................................ . . LH side rail at rear crossmember (Suburban) ............ . 191 C300B ............................................. . . LH side rail at rear crossmember (Utility)..................... . 192 C300B ............................................ . . LH side rail at rear crossmember (Fleetside).............. . 192 C300B ............................................ . . LH side rail at rear crossmember (Suburban) ............ . 191 C301 ............................................... . . Above rear crossmember, towards LH side of vehicle . . 8 C303 ............................................... . . At LH frame rail near fuel tank ...................................... . 175 C305 ............................................... . . At fuel tank selector valve and motor switch .............. . 176 177 C306 ............................................... . . At LH safety b e lt................................................................ . 181 C309 ............................................... . . At shift le v e r....................................................................... . 182 C310 ............................................... . . At fuse block .................................................................... . 183 183 . C311 .............................................. . . . In LH kick p a n e l................................................................ 181 C312 .............................................. . . . In LH kick p a n e l................................................................ . 181 C313 .............................................. . . . RH side of fuse b lo c k ...................................................... . 182 C323 .............................................. . . . At RH side of l/P ............................................................... . 186 C324 .............................................. . . . At RH vanity m irror........................................................... . 186 C400 .............................................. . . . At door panel contactor ................................................. . 188 C401 .............................................. . , . At door panel contactor .................................................. . 188 C402 ............................................ . . . At LH B-pillar .................................................................... . 188 C403 ............................................ . . . At RH B -pillar.................................................................... . 188 C404 ............................................ . . . At RH B -pillar.................................................................... . 188 C405 ............................................ . . . LH side rear crossmember (Utility) ............................... . 189 C406 ............................................ . . . LH side rear crossmember (Utility) ............................... . 189 C409 ............................................ . . . At fuel pump and sender ............................................... . 175 176 177 . 176 C410 ............................................ . . . At RH auxiliary fuel t a n k ................................................. 177 180 . 168 C411 ............................................ . . . At RH tail, stop and turn lam p ........................................ 168 169 C412 ............................................ . . . At LH tail, stop and turn la m p ........................................ . 168 168 169 C413 ............................................ . . . At LH rear side marker la m p .......................................... . 168 168 C414 ............................................ . . . At RH rear side marker lam p.......................................... . 168 168 C415 ............................................ . . . At RH side front clearance la m p ................................... . 168 C416 ............................................ . . . At RH side rear clearance lamp ................................... . 168 C417 ............................................ . . . At LH side front clearance lamp ................................... . 168 C418 ............................................ . . . At LH side rear clearance la m p ...................................... . 168 C419 ............................................ . . . Rear lamp harness, towards LH side of veh ic le......... . 168 C420 ............................................ . . . At RH license la m p ........................................................... . 191 C300 8 9 82 83 84 82 83 84 82 8 27 34 35 50 52 54 55 48 48 51 61 61 68 68 71 71 68 72 72 27 34 35 34 35 46 8 9 11 8 9 11 8 9 8 9 10 10 10 10 9 80 COMPONENT LOCATION C421 C423 C424 C425 C426 C427 C428 ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... C429 ............................................... . . At LH backup lam p ........................................................ C430 C431 C432 C433 C434 ............................................... ............................................... ............................................... ............................................... ............................................... C435 ............................................... . . In LH B-pillar .................................................................. C436 C437 C438 C439 C440 C442 C447 C448 C449 C450 C451 C452 C453 C454 C455 C456 C500 C501 ............................................... , . ............................................... , . ............................................... , . ............................................... . ..............................................., . ............................................... . ................................................ . ..............................................., . ..............................................., . ................................................ . ................................................ . ................................................ . ................................................ . ................................................ . ................................................ . ..............................................., . ................................................ . ................................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . At LH license la m p ........................................................ Rear lamp harness, LH side inside harness wrap . . Rear lamp harness, RH side inside harness wrap . . At rear heater blower motor ........................................ At rear heater blower motor ........................................ At rear crossmember, towards LH side of vehicle . . At RH backup lamp ...................................................... At LH B-pillar At LH B-pillar At LH B-pillar At LH B-pillar In LH B-pillar .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. At cargo lamp ............................................................... At LH rear door jamb sw itch ........................................ At RH rear door jamb switch........................................ At LH rear s p ea k er........................................................ At RH rear speaker........................................................ At RH rear gate s w itc h ................................................. Under LH side of rear bumper (suburban) .............. Under LH side of rear bumper (suburban) .............. Below bumper on LH side .......................................... At LH panel door lock actu ato r................................... At LH panel door lock actuator................................... At RH panel door lock actuator................................... At RH panel door lock actuator................................... In LH B-pillar .................................................................. In LH B-pillar .................................................................. Rear of vehicle in roof p a n e l........................................ At LH power window switch (2-door).......................... At LH power door lock sw itch...................................... C502 ................................................ . . At LH front power door lock actuator ........................ C503 ................................................ . . At LH power window m otor.......................................... C506 ................................................ . . At LH power window switch (4-door).......................... C508 ................................................ . . At LH power m irror........................................................ C509 ................................................ . . At upper LH front d o o r ................................................. C600 ................................................ . . At RH power mirror........................................................ C602 ................................................ . . At RH power door lock switch..................................... C603 C604 C700 C701 C702 ................................................ ................................................ ................................................ ................................................ ............................................. . . . . . . . . . . . At At At At At RH front power door lo c k ........................................ RH power window motor ........................................ LH rear window s w itch ............................................. LH rear power window m o to r ................................. LH rear power door lock actuator.......................... Page - Figur 191 80 168 9 168 9 181 48 181 48 169 12 168 8 168 9 169 11 . . 168 8 168 9 169 11 . . 187 65 . . 187 65 . . 187 65 . . 187 65 . . 185 59 185 60 . . 185 59 185 60 . . 187 65 . . 185 60 . . 185 60 . . 193 88 . . 193 88 . . 186 64 . . 189 73 . . 189 73 . . 190 75 . . 190 77 . . 190 77 . . 190 76 . . 190 76 . . 187 65 . . 187 65 . . 186 64 . . 188 69 . . 188 69 188 70 . . 188 70 . . 188 69 . . 188 69 . . 188 69 . . 188 69 . . 188 69 . . 188 69 188 70 . . 188 70 . . 188 69 . . 188 71 . . 188 71 . . 188 71 . . . . . . . . . . . . . . COMPONENT LOCATER INDEX A-199 COMPONENT LOCATION Page - Figure ___ 188 ___ 188 ___ 188 ___ 188 ___ 188 ___ 188 ___ 189 189 ___ 189 189 ___ 189 189 ___ 190 ___ 190 . . . . 190 ___ 190 ___ 190 . . . . 190 ___ 190 71 71 71 68 68 68 72 73 72 73 72 73 77 76 77 77 76 75 75 . . Engine compartment, RH C o w l............................... ___ 179 . . Engine compartment, RH C o w l............................... ___ 171 173 174 177 178 ___ 173 ............................................. . . Engine compartment, near LH cylinder head 174 175 177 178 ............................................. . . Cowl panel, above transmission tu n n e l................ ___ 180 180 ............................................. . . Engine compartment, LH C o w l............................... ___ 166 166 167 ............................................. . . Engine compartment, top LH side of c o w l............ ___ 182 183 ............................................. . . Cowl panel, above transmission tu n n e l................ ___ 176 187 ___ 168 ............................................. . . LH rear lamp harness, below RH rear lamps ___ 168 ............................................ . . LH rear lamp harness, below LH rear lamps ............................................ . . LH side at kick panel ............................................... ___ 187 188 ............................................ . . Between front LH door jamb and door ................. ___ 188 ............................................ . . At LH A-pillar ............................................................. ___ 185 ............................................ . . RH side at kick p a n e l............................................... ___ 187 ............................................ , . . Between front RH door jamb and d o o r ................ ___ 187 ............................................ , . . At RH A -p illar............................................................. ___ 185 ............................................ , . . Between B-pillar and LH rear door ........................ ___ 188 ............................................ . . . Between B-pillar and RH rear d o o r ........................ ___ 188 43 19 23 25 36 39 23 25 29 36 39 47 45 2 3 4 51 55 33 66 8 8 67 69 69 60 67 67 60 71 71 .. .. .. .. .. .. .. At At At At At At At RH rear window sw itch........................................ RH rear power window m o to r............................ RH rear power door lock actuator..................... rear panel door lock actu ato r............................ rear panel door contactor, door s id e ................ rear panel door contactor, door s id e ................. cut-out switch......................................................... C800 C801 C802 C900 C901 C902 C904 ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... ............................................... C905 ............................................... . . At tailgate window motor ........................................ C906 ............................................... . . C907 ............................................... C908 ............................................... C909 ............................................... C910 ............................................... C911 ............................................... C912 ............................................... C913 ............................................... Grommets: GT100 ............................................. GT101 ............................................. GT102 GT103 GT105 GT106 GT107 GT400 GT401 GT500 GT501 GT502 GT600 GT601 GT602 GT700 GT800 .. .. .. .. .. .. .. At tailgate window switch (key operated) ............ In top LH panel door ............................................... In top RH panel d o o r ............................................... At LH panel door lock actuator............................... At LH panel door lock actuator............................... At RH panel door lock actuator............................... At top LH side of tailgate ........................................ At center LH side of ta ilg a te ................................... A-200 COMPONENT LOCATER INDEX COMPONENT LOCATION Page -- Figure Grounds: G105 ............................................... . . LH front of vehicle, above LH headlamps ................. . . 166 166 G106 ............................................... . . RH front of vehicle, above RH headlamps................. . . 166 166 G107 ............................................... . . RH front of vehicle on frame below RH headlamps . . . 166 166 G108 ............................................... . . In engine, compartment above auxiliary battery junction block................................................................. . . 192 G109 ............................................... . . LH side of vehicle on radiator support........................ . . 192 G110 ............................................... . . Top RH rear of engine ................................................. . . 172 179 G110 ............................................... . . Top RH front of engine................................................. . . 173 G111 ............................................... . . RH front of vehicle above RH battery ........................ . . 170 172 G112 ............................................... . . Front of RH cylinder h e ad ............................................ . . 171 G113 ............................................... . . Front of LH cylinder h e a d ............................................ . . 170 G114 ............................................... . . At alternator bracket..................................................... . . 170 G115 ............................................... . . Rear of RH cylinder h e a d ............................................ . . 173 174 G117 ............................................... . . Above blower motor in engine compartment............ . . 179 G118 ............................................... . . In engine compartment at top of c o w l........................ . . 186 G200 ............................................... . . LH side of l / P ................................................................. . . 167 180 182 183 187 G201 ............................................... . . Under l/P near fuse panel............................................ . . 176 183 183 190 G401 ............................................... . . At LH rear crossmember (Suburban) ........................ . . 189 G402 ............................................... . . RH rear side of vehicle................................................. . . 168 168 G403 ............................................... . . LH rear side of v e h ic le ................................................. . . 168 168 G403 ............................................... . . LH side rail at rear crossmember .............................. . . 191 192 G404 ............................................... . . Under tailgate near LH side of vehicle....................... . . 169 G406 ............................................... . . LH rear side of v e h ic le ................................................. . . 169 G407 ............................................... . . RH rear side of vehicle................................................. . . 169 G409 ............................................... . . LH frame rail above fuel tank ..................................... . . 175 176 177 G410 ............................................... . . RH rail above fuel ta n k ................................................. . . 176 177 G411 ............................................... . . Above rear blower motor ............................................ . . 180 190 G904 ............................................... . . At rear tailgate window motor (Suburban)................ . . 189 2 3 2 3 2 3 85 85 22 42 24 18 22 21 18 18 24 26 43 63 6 47 53 54 67 33 54 55 74 73 8 9 8 9 82 84 12 11 11 27 33 35 34 35 46 77 73 COMPONENT LOCATION Page -- Figure Splices: S 1 0 0 ................................................. . . Engine harness, near junction b lo c k .......................... . . 173 175 S 1 0 1 ................................................. . . Engine harness, front of LH valve cover ................... . . 174 S 1 0 3 ................................................. . . Engine harness, near starter m o to r............................ . . 172 174 S 1 0 4 ................................................. . . At LH inner fender w e ll................................................. . . 192 S 1 0 5 ................................................. . . At LH inner fender well near auxiliary battery re la y .................................................................... . . 192 S 1 0 6 ................................................. . . Engine harness, near junction b lo c k .......................... . . 174 S 1 0 7 ................................................. . . Engine harness, near g en erato r................................. . . 172 S 1 0 8 ................................................. . . Engine harness, near starter m otor............................ . . 172 S109 . . ............................................. . . Engine harness, near center of e n g in e ..................... . . 175 S 1 0 9 ................................................. . . Engine harness, top rear ............................................. . . 172 S 1 1 0 ................................................. . . Forward lamps harness, LH s id e ................................. . . 166 S 1 1 1 ................................................. . . Forward lamps harness, in front of RH headlam ps............................................................... . . 166 166 S 1 1 2 ................................................. . . Forward lamps harness, in front of LH headlamps...................................................................... . . 166 166 S 1 1 3 ................................................., . . Forward lamps harness, LH side behind headlamps...................................................................... . . 166 S 1 1 4 .................................................. . . Forward lamps harness, LH side in front of washer b o ttle .................................................................. . . 166 S 1 1 7 .................................................. . . Engine harness, rear top of e n g in e............................ . . 173 174 520 24 28 26 22 25 85 85 26 22 22 28 22 2 2 3 2 3 3 3 23 26 S 1 1 8 .................................................. . . At LH inner fender well near auxiliary battery relay . . . 192 S 1 1 9 .................................................. . . Engine harness, center of RH valve c o v e r................ . . 172 177 S121 (6.2L Diesel)......................... . . . Engine harness, rear top of e n g in e............................ . . 130 S130 (6.2L HD D iesel).................. . . . Engine harness, rear top of e n g in e............................ . . 130 S 1 3 6 .................................................. . . Engine harness, RH side of e n g in e ............................ . . 172 173 174 S 1 3 7 .................................................. . . Engine harness, RH side of e n g in e ............................ . . 172 173 174 S 1 3 8 ............................................... . . . Under l/P near E C M ...................................................... . . 175 S 1 3 9 ............................................... . . . Engine harness, rear top of e n g in e ............................ . . 173 174 85 25 36 28 28 22 24 25 22 23 25 29 23 26 S 1 4 0 ............................................... . . . Engine harness, rear top of e n g in e ............................ . . 173 174 23 26 S 1 4 5 .............................................. S 1 6 9 .............................................. S 1 7 1 .............................................. S 1 9 7 ............................................... S 1 9 8 ............................................... S 1 9 9 .............................................. . . . . . . . . . . . . . . . . . . LH side of cowl panel near antilock control module . Engine harness, RH rear of e n g in e ............................ Engine harness, center of LH valve c o v e r................. Engine harness, rear center of engine ..................... Engine harness, rear center of engine ..................... Engine harness, rear center of engine ..................... . . . . . . . . . . . . 178 172 175 175 175 175 COMPONENT LOCATION 40 22 28 28 28 28 1 5202 5203 5205 5206 5207 5209 521 521 0 1 521 2 521 3 S 2 1 5 .......................................... 521 7 521 8 5257 5258 5259 5260 526 1 5300 530 1 5302 S304 ........................................ 5304 5305 5305 5306 5306 5307 5307 5308 S 3 1 0 ........................................ 531 2 531 3 5326 5327 5328 5329 5400 540 1 Page -- Figure l/P harness, LH s id e ........................................................... 167 4 193 87 l/P harness, LH s id e ........................................................... 167 4 l/P harness, LH s id e ........................................................... 167 4 179 41 l/P harness, behind steering column support .............. 183 54 183 55 l/P harness, LH side of steering column ........................167 5 l/P harness, bottom of steering colum n..........................167 5 l/P Harness, LH side under l/P ........................................ 167 4 193 87 l/P harness, LH s id e ........................................................... 167 4 l/P harness, behind steering column support .............. 183 54 183 55 l/P harness, LH side under l/P ........................................ 167 4 l/P harness, above ra d io .................................................... 179 41 l/P harness, LH s id e ........................................................... 167 4 l/P harness, above fuse b lo c k .......................................... 185 60 l/P harness, above glove b o x ........................................... 185 60 l/P harness, beneath l / P .................................................... 187 67 l/P harness, beneath l / P .................................................... 187 67 l/P harness, beneath l / P .................................................... 187 67 l/P harness, behind l/P cluster ........................................ 187 67 188 69 l/P harness, behind l/P cluster ........................................ 187 67 188 69 Rear lamps extension harness, at rear crossmember . 170 16 Rear lamps extension harness, at rear crossmember . 170 16 Rear lamps extension harness, at rear crossmember . 1 6 8 8 170 16 82 LH side rail at rear crossmember (Suburban) .............. 191 192 83 LH side rail at rear crossmember (Fleetside)................ 192 84 LH side rail at rear crossmember (Suburban) .............. 191 82 192 83 84 LH side rail at rear crossmember (Fleetside)................ 192 LH side rail at rear crossmember (Suburban) .............. 191 82 192 83 LH side rail at rear crossmember (Fleetside)................ 192 84 LH side rail at rear crossmember ................................... 191 82 192 83 LH side rail at rear crossmember (Fleetside)................ 192 84 Rear lamps extension harness, at rear crossmember . 168 8 l/P harness behind LH kick panel ................................... 188 69 l/P harness behind LH kick p a n e l................................... 188 69 l/P harness behind LH kick p a n e l................................... 188 69 Auxiliary fuel tank harness, at crossm em ber................ 176 34 Auxiliary fuel tank harness, at crossmember ................. 176 34 Auxiliary fuel tank harness, at crossm em ber................. 177 35 Auxiliary fuel tank harness, at crossm em ber................. 177 35 Rear of vehicle at top LH s id e .......................................... 190 77 Rear of vehicle at top LH s id e .......................................... 190 77 COMPONENT LOCATER INDEX A-201 COMPONENT LOCATION Page - Figure 8 S 4 0 2 .................................................. . . LH rear lamp harness, above rear crossmember . . . . . 168 168 9 8 S 4 0 3 .................................................. . . RH rear lamp harness, below RH rear lam ps......... . . . 168 168 9 9 S404 ................................................. . . Rear lamp harness, near center of vehicle ............ . . . 168 8 S405 ................................................. . . RH rear lamp harness, below RH rear lam ps......... . . . 168 8 S406 .................................................. . . LH rear lamp harness, above rear crossmember . . . . . 168 9 S 4 1 0 ................................................. . . Rear lamp harness, toward LH side of vehicle . . . . . . . 168 80 S 4 1 1 ................................................. . . Rear center of vehicle behind bumper ................... . . . 191 S 4 1 2 .................................................. . . Rear dome lamp harness, behind LH B-pillar, 59 above LH rear door .................................................... . . . 185 51 S 4 1 3 ................................................. . . Rear dome lamp harness, above LH rear door . . . . . . 182 72 S908 ................................................. . . RH side of tailgate (Utility) ........................................ . . . 189 73 S908 ................................................. . . LH side of tailgate (Suburban) ................................. . . . 189 73 S909 ................................................. . . LH center of tailgate (Suburban)............................... . . . 189 72 S909 ................................................. . . Center of tailgate (Utility) .......................................... . . . 189 A-202 COMPONENT LOCATER INDEX SECTION B P MODEL (COMMERCIAL) SECTION B - P-MODEL B-1 BULKHEAD CONNECTOR (SEE PAGES 4, 5) BATTERY JUNCTION BLOCK (SEE PAGES 4,5) STEERING COLUMN SWITCHES (SEE PAGES, 32, 34) DRL RELAY (SEE PAGE 28) FUEL TANK SENDER (SEE PAGE 54) BATTERY (SEE PAGES 4,5) REAR LAMPS HARNESS (SEE PAGE 76) FUEL PUMP RELAY (SEE PAGE 48) REAR BODY CONNECTOR (SEE PAGE 54) 8-2 PHANTOM VIEW ESC MODULE (SEE PAGE 42) SYMPTOMS INDEX SYMPTOM PAGE BRAKE WARNING SYSTEM Brake indicator remains on with ignition switch in RUN and park brake o f f ............................................. B-73 Alarm will not s o u n d ........................................................................................................................................... B-73 Alarm will not shut o f f ................................................................................................................. ....................... B-73 DIESEL ENGINE FUEL CONTROLS Fuel heater does not o p e ra te ........................................................................................................................... B-62 Water in fuel indicator lights with no water in fuel ........................................................................................B-62 Water in fuel indicator does not light briefly with ignition switch turned to RUN ....................................B-62 GAGES AND INDICATORS Fuel gage indicates full or beyond at all tim e s ...............................................................................................B-66 Fuel gage indicates empty when there is fuel in the ta n k ............................................................................ B-66 Fuel gage is inaccurate ...................................................................... ......................................................... B-66 Temperature indicator stays on at all times with ignition switch in RUN .................................................. B-66 Temperature gage indicates cold all the time ...............................................................................................B-67 Temperature gage is in a cc u ra te ...................................................................................................................... B-67 Temperature gage indicates hot with engine coolant below operating temperature and ignition switch in R U N ..................................................................................................................................................B-67 Oil pressure gage is not a ccu ra te .................................................................................................................... B-67 Oil pressure gage indicates high pressure at all tim e s .................................................................................B-67 Oil pressure gage indicates low pressure when oil pressure is g o o d .......................................................B-67 Low coolant indicator does not light with coolant level low (diesel o n ly ) ..................................................B-67 Low coolant indicator is lit when coolant level is g o o d .................................................................................B-68 REAR EXTERIOR LAMPS None of the rear lamps operate .................................................................................................................. b -75 Backup lamps do not operate...................................................................................................................... b -75 START AND CHARGE Starter solenoid clicks, engine does not crank or cranks slowly.............................................................. b -39 Engine does not crank and starter solenoid does not click .................................................................... b -39 Battery is undercharged or overcharged.................................................................................................... b -39 TURN LAMPS Turn signals do not o p e ra te ........................................................................................................................ b -33 Turn signals do not operate on one side.................................................................................................... b -33 Turn signal lamps flash rapidly.................................................................................................................... b -33 WIPER/WASHER Wipers do not operate in any mode ........................................................................................................... b -37 Wipers do not operate in HI ........................................................................................................................ b -37 Wipers do not operate in L O ........................................................................................................................ b -37 Washer motor does not operate................................................................................................................. b -37 Washer motor does not shut o f f ................................................................................................................. b -37 GLOW PLUGS Wait indicator does not flash or flashes for the incorrect amount of time when engine is below operating tem perature........................................................................................................................ B-59 HEADLAMPS Headlamps do not illuminate high or low beams - both sides .................................................................. B-22 Low beam lamp(s) do not operate ..................................................................................................................B-22 High beam lamp(s) do not o p e ra te ..................................................................................................................B-22 HEADLAMPS (WITH DRL) Headlamps do not illuminate high or low beams - both sides .................................................................. B-25 Low beam lamp(s) do not operate ..................................................................................................................B-25 High beam lamp(s) do not o p e ra te ..................................................................................................................B-26 Canadian daytime running lamps do not operate ....................................................................................... B-26 HORNS Hom(s) will not operate ....................................................................................................................................B-35 Horn sounds continuously without depressing horn switch ....................................................................... B-35 PARK, MARKER AND HAZARD LAMPS Park lamps do not o p e ra te ............................................................................................................................... B-30 Hazard warning lamps do not operate .......................................................................................................... B-30 Side marker lamp(s) do not o p e ra te ............................................................................................................... B-30 Rear marker lamp(s) do not o p e ra te ............................................................................................................... B-30 SYMPTOM INDEX B-3 RPOCODES g . ._ _ _ _ _ _ 2-32.0 BLK _ _ _ _ _ _ _- . B3D - SCHOOL BUS EQUIPMENT CLUTCH START SWITCH . .- - - - - 6-3,0 PPL _ _ _ _II . ._ _ 5-3,OYEL _ _ _. _ ,11______ 1-19.0 BLK _ _ _ _• 'r.-~: 3 2_ BATTERY ~ 0 0 0 0 8917053 1000001 i BODY BUILDER 100 AMP JUNCTION BLOCK (B3D ONLy) ~ ~ 0 S207 I C298 1201966 51 -----. ai ~ II: C299 6294641 ~ • • _ _ _ _ 4-5,0 BRN _ _1 ____________ 300-5,00RN HEADLAMP SWITCH J K 150-+--_ PANEL DIMMER SWITCH \o:...J ira: STARTER MOTOR 00 ~;g 2 0 w if 0 III II: ~ o 12020030 -.S205 _ _ __ S198. • ~ C209 12020029 _ @ BREAKER 25AMP .;; Cl00 '" 12020184 . .- - - - - 1 _ 2 - 5 , O R E D _ _ _ _ _ _ S208 (SEE PAGE 70) :5III 0 oj \ . 0 N ~ ENGINE ~ 3 = 4O-t--- ~8A~ @ [g~ m [BJ POWER DISTRIBUTION GASOLINE ENGINES WIMAN TRANS IGN a , ~ = Cl00 12020183 Z HTR PWR IGNITION COIL (SEE PAGE 42) QRA~ ~ TAIL LPS INJ HTR ACC-RADIO S~ ECM-CRNK AUX WIPER if 0 III o ~~OO~ HTR 25 AMP LIGHT SWITCH ~~ ALT CRNK TQ5J Qsp~ INSTR-LPS 5AMP 51 II: o "1 ECM-BAT 10 AMP 10AMP ACC-RADIO TAIL LPS 20 AMP -;rir-..!~~~h::~~ STOP-HAl 15AMP ns:l~DD~ o SHEET METAL GROUND G110 IQQS HEAO -- -II: ~DD~qwp ~M 'PARK --~"'r-I 0 m:l@@omoo ACC OFF ---. L --~I_:r ~ ENGINE GROUND G111 I 0 Sl11 (SEE PAGE 46) -- 6-3,0 PPL _ _ _ _2-5,ORED_ I/PCLUSTER (SEE PAGE 70) ~ _ _3-5,OPNK_ S197 @~ 2-5,0 RED _ _ _ _ _ __ . . . . " . . . . " ...." m:l m:l @ ill~ m [BJ 0 Cl0B 12045896 _ II :5III ...J £l.. £l.. L GENERATOR -'o:H;::"EA"Orl--t-- 10 '9-1,OBRN - - - - - NI:!:- I L • STARTER MOTOR • S198. Sl92 N l~~ P d! Il?;::)M N ~,Q1 co ~ Cl00 12020184 ~ _2-S.0RED . S199 • 2-1.0 RST (FUSIBLE LINK) '" • _ oj -b S197 Slll ._ (SEEP~~ C106 12045896 c;j a N ~ a 3 L ~ _ _ = _ _ _• HEAD .9-1.0BRN \ , ~ .--------- ~8A~ ~ m~ OJ _ 3-S.0 PNK _ _ _ __ _ 2-S.0 RED - - - - . 'PARK ---- lID lID ~ ill ~ OJ HTR 2SAMP GAUGES 20 AMP HORN/DM lSAMP lID 0 z [ffi Z a: 0 IGN HTR PWR GAUGES a: 0 '" o ~OOOODD ECM-BAT 10 AMP PWR TAIL LPS 20 AMP OOOODOc=J HORN/OM INSTR-LPS , TAIL LPS ~ , ~ if a ~,a M -- -ENGINE GROUND G111 TRANS ECM-BAT HTR ACC-RADIO OO~OOOO co SHEET METAL GROUND G110 IGNITION COIL (SEE PAGE 42) Cl00 12020183 9 • • L ACC if 10 OFF 300-S.0 ORN _ _ _• IID!ID~OOJOO ... _ , 40-+-......- . S206 I/PCLUSTER (SEE PAGE 70) D;;: ~ a C209 12020029 _ ENGINE ~ ~ -~7i1 AI 39-.8 PNKlBLK • (SEE PAGE 70) ~ ..J Q. Q. '-,PARK I _2-S.0 RED _ _ _ _ _ __ S208 :s '"a a 1tIl: ._S2.1~.~.~ .7_~ ~~:i ",0 156 DOME CIRCUIT BREAKER 25AMP w 0w a: a: q 150-~-_ 2 D M qUiD GENERATOR HEADLAMP SWITCH 1 12" INJ 15AMP nstl~ODOO S~ ECM-CRNK AUX WIPER o 00 00 ~ Qspg ALT CRNK FRONT 12089776 CRNK 10AMP POWER DISTRIBUTION GASOLINE ENGINE W/AUTO TRANS B-5 RPOCODES • _ _ _ _ _ _ 6-3.0 P P l - - - - - - - - - - e ,A B 5-3.0 YEl _ _ _ _ _ _ _ _ _ _ ._ S6 • ___ l CLUTCH START SWITCH B3D - SCHOOL BUS EQUIPMENT IGNITION SWITCH C219 8911921 LH BATTERY RH BATTERY o w a: 8917053 0 10 0 0 0 01 o ai N _L 0 C298 1201986 1-32.0 BlK (B3D ONLy) C299 6294641 3-5.0 PNK ~ STARTER MOTOR ~ 7' II~-" 'iC5~ ~ q I-Z ~ (f) ~ :J M Q;! N~ \!:- I • S195 I C191 _ ~ v • ~........:;:-;:;, ~ 2-1.0RST_ (FUSIBLE LINK) - 2-13.0 RED_._ _ (~ S197 ~2-1.0RS~._2-3.0RED' (FUSIBLE LINK) GLOW PLUG CONTROLLER - • 3 6 '" ~ ,~" a: & CD CD M q a q q a 01 - cw'"" M , . , eN",,", - - '" (SEE PAGE 70) (SEE PAGE 70) a ::"".·_~ _~2 :2 ~t. ~ .,~-it!~m~t3jfilT-;~'=:'-, ENGIN-l-= GROUND RH 0 -,- SHEET METAL CYLINDER GROUND HEAD G113 G110 DIESEL ENGINE WIMAN TRANS 7-1 £AI L U!J ~ III ~ ITl lHl 0 L ACC ~ ~ DmDD IGN HTR PWR DO 00 0 0 00 O~ L.r-.J l o M TRANS ECM-BAT ' H"" •____ 00 OHTRO A~O AUX STOP-HAZ ECM-CRNK ~ t? 11~ • o a: co o o ECM-BAT 10AMP HORN/DM 15AMP [jUG ~~~~ ~ ~ Z lID lID !Al III ~ ill [ill 0 IIDIID@ . , 'PARK _--"'!oiH-, LIGHT SWITCH HORN/OM ~ INSTR-LPS t;-;;-fl o 300-5.0 ORN _ _ __ 4O-1---~ HEAD £ATir -- - GENERATOR 10 OfF .--------.;. 12015982 POWER DISTRIBUTION -.S205 HEAD Cl00 12020184 2-5.0 RED _ _ _ _ _ _ __ 1 a ffi ffi I HI ~ • ---- ------~ : - 12020030 5 ~ 0 c::::::;, 0 ~--------"" 5 ENGINE GROUND LH CYLINDER HEAD G113 2 CIRCUIT BREAKER 25 A .... ~ c 156 150-.---- PANEL DIMMER SWITCH S192 @@"' B-6 0 _ _ _ _ _ 4-5.0 BRN _ -1-----1 -- .. -- (B3D) ~~ (FUSIBLE LINK) ' J 300-5.00RN "_~ t0~2-1.0RST_ I II • START RUN OFF LOCK 0 0 44 ~t!~~------6-3.0 PPl _ _ _ _ _ _. . . BATTERY JUNCTION BLOCK 0 B c BODY BUilDER 100 AMP JUNCTION BLOCK (B3D ONLy) . ._ _ 1-50.0 BlK _ _ _ _ __ ~': f.~t o 2-13.0 RED (B3DONly) + + 4 ~~ ALT ACC-RADIO 10AMP ~ WIPER CRNK T~ QS/P~ ECM-CRNK 10AMP fRONT FUEL SHUT OFF VALVE (SEE PAGE 63) FUSE BLOCK 12089776 CRNK 10AMP TURN-B/U 15AMP 20 AMP RPO CODES B3D - SCHOOL BUS EQUIPMENT IGNITION SWITCH 3 + LH BATIERY 1000 0 01 N B BODY BUILDER 100 AMP JUNCTION BLOCK (B3D ONLy) . ._ _ 1-S0.0 BLK _ _ _ _ __ 1-32.0 BLK (B3D) fj~~~ _____ 6-3.0 PPL _ _ _ _ _ _. . . START RUN 1 OFF LOCK ACC 44 ..._ _ _ _ _ 4-5.0 BRN _ 300-S.0 ORN K S196 - - 1....,~_It:I=tttL ".-YI-+---i • PANEL DIMMER SWITCH B z a: o .,; N -. "J '-0'-o:=="..-'~ ~ ----- ~ ------"'" tJ C100 12020184 co ~ -' "q • "- @cr: 0: o 0 "-0 . _,' -~ 3-3.0PNK. ;;; - E C128 '" u;>" ~ ..~~ q a C\I d ~ ~ _I_.!-_. 1201S982 ENGINE GROUND LH CYLINDER HEAD G113 ~~ ~ 0 [ l .. @ ~ ~ ~ I/P CLUSTER S206 (SEE PAGE 70) ~ £AT@ -, ~o _ 3-S.0 PNK _ • _ 2-S.0 RED _ _ ~ [g~CD _ [IDlID~D[i]DD = ~---------------------' sa ----. --.~ M "o N oj SHJET METAL CYLINDER GROUND HEAD G113 G110 Z ~ o a: 0 0 HORN/OM lSAMP • l TRANS ECM-BAT HTR ACC-RADIO AUX WIPER INJ STOP-HAZ ECM-CRNK c? I ALT Sl13 c=J TAIL LPS 20 AMP 00D800~ ~~DDOO o 00 [}?f] TAIL LPS INSTR-LPS SAMP --- i - ............. -------J .. HTR PWR [jUG HORN/OM INSTR-LPS --~t--I-, LIGHT SWITCH ~DDOODD ~ 00 O ~ O -1 O_ -:::=- IGN HTR 2SAMP __ z lID lID ~ m~ CD [BJ 0 ACC I [BJ 0 L o RH S299 • _ _ __ 44-1.0DKGRN _ _ -- . I .9-1.0BRN ------- ________ CIRCUIT BREAKER 25 AMP ~ -.... ~~g~%~ I~ _ .. .--11- - Cl07 12045896 I ... C209 12020029 300-S.0 ORN _ -2-S.0RED-------7i- 39-.8 PNK/BLK S208 (SEE PAGE 70) s~~~~~~30 DOME 2 tD "? .......-+--il-- 156 150-~-_ F o N C A ~1 M E ~ M 6 ~ o L o S192 HEADLAMP SWITCH -- --11·-----------1 ~ -- .. GENERATOR C299 6294641 3-S.0 PNK STARTER MOTOR !I~: 0 o C298 1201966 - BATTERY JUNCTION BLOCK • o 89170S3 ai ;Jj'~. 2 0 cr: o + RH BATIERY (B3D') - 4 ow 2-13.0RED~ lSAMP CRNK T~ Qs/pQ FRONT 3-3.0PNK _ _ _ _. . .~ FUEL SHUT OFF VALVE (SEE PAGE 63) FUSE BLOCK 12089776 GAUGES 20 AMP TURN-B/U 15 AMP POWER DISTRIBUTION DIESEL ENGINE W/AUTO TRANS B-7 RPOCOoES 2-13.0REo~ (B30) I II: o _ _ _ _ _ _ _ _ _ _ _ 6-3.0PPl _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. . 8917053 LH BATTERY RH BATTERY 100 0001 GT104 + + ow MTI - AUTO TRANS, Ho, 4-SPO., WITH OVERDRIVE MT8 - MAN TRAN8, 5-SPO., WITH OVERDRIVE BODY BUILDER 100 AMP JUNCTION BLOCK . ._ _ _ _ _ 3-3.0 PNK _ _ _ _ _. . ...J ~ ~ N o Cl00 12020164 lIP -------BGl . .- - - - - - 1-50.0 BlK 1-32.0 BlK (B30) BATTERY JUNCTION BLOCK B STARTER MOTOR It--~I-{r ---. ---- ---. o I ~=--+-i'-; ~ I- ~ (J) -' / \ \ \ ~2-1.0RST-.-2-3.0RED~ (FUSIBLE LINK) S 197 q ffi CO? (jj i~ • I oW II: o BAT 1 m 0 mi> L 0 □ (U S I 0 0S (El □ [3 ® 0 □ ACC gcg m □ s □ □ [M] □ 0 K l K PWR [X ] K ] D _3_ K l [Jt] D3 Dd □ D D§] EG 0 D IM1P o HORN/DM INSTR-LPS TAIL LPS 350-.8 PNK/WHT - FUEL CYC MDL 250-1.0 BRN - TRANSMISSION 440-1.0 ORN - ECM 2-5.0 RED - BATTERY 50-3.0 BRN 300-5.0 ORN - IGNITION □ □ m IGN HTR PWR GAUGES _15A^_ 090 □ L B] \B INJ STOP-HA : ECM-CRNK TRANS ECM-BAT HTR ACC-RADIO AUX WIPER ALT CRNK t Or n -b Tu fus / p lr 240-1.0 ORN - HORN RLY - DOME LAMP SHUNT 12041235 8-.8 GRA - INSTRUMENT LAMPS 8-1.0 GRA --------------------------------------------- 44-1.0 DK GRN - LT SW RHEOSTAT 40-1.0 ORN • TAIL LAMPS 481-1.0 RED - INJECTORS -141-1.0 BRN/WHT 4-5.0 BRN - IGN SW 93-3.0 WHT - WINDSHIELD WIPER 140-1.0 ORN - STOP LAMP SW - HAZ FLSHR 439-1.0 PNK/BLK - ECM (FUSED) 16-.8 PPL - TURN SIGNAL SW 75-.8 DK BLU - BACK-UP LAMP SW 3-5.0 PNK - IGNITION 3-5.0 PNK - IGN SW - ENG IGN 39-.8 PNK/BLK - INSTRUMENT CLUSTER 39-1.0 PNK/BLK - ALTERNATOR - EGR SOLENOID FRONT 12034359 - BLOCK MOLD 12089776 - PRINTED BLOCK 38-.8 DK BLU - TURN SIGNAL ■ COLOR MALE CONN A BRN 12004887 B BLK 12004886 H GRN 12004885 1 NAT 12004888 L BLU 12004884 FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION INJ 12004006 BRN 7.5 AMP HOT IN RUN OR START ALTERNATOR INSTR-LPS 12004005 TAN 5 AMP HOT W/ HEADLAMP IN PARK OR HEAD ELECTRONIC CONTROL MODULE STOP-HAZ 12004008 LT BLUE 15 AMP HOT AT ALL TIMES STOP LAMPS HAZARD FLASHER TAIL LPS 12004009 YELLOW 20 AMP HOT AT ALL TIMES TAIL LAMPS PROVISIONS FOR GAGES TRANS 12004007 RED 10 AMP HOT IN RUN OR START TRANSMISSION PROVISIONS FOR HORN AND DOME LAMPS TURN-B/U 12004008 LT BLUE 15 AMP HOT IN RUN OR START TURN SIGNALS BACK-UP LAMPS WIPER 12004010 WHITE 25 AMP HOT IN ACC OR RUN DESCRIPTION FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION ACC-RADIO 12004007 RED 10 AMP HOT IN ACC OR RUN RADIO ACCESSORIES ALT 12004009 YELLOW 20 AMP HOT IN RUN OR START ECM-BAT 12004007 RED 10 AMP HOT AT ALL TIMES ECM-CRNK 12004007 RED 10 AMP HOT IN RUN OR START GAUGES 12004009 YELLOW 20 AMP HOT IN RUN HORN-DM 12004008 LT BLUE 15 AMP HOT AT ALL TIMES HTR 12004010 WHITE 25 AMP HOT IN RUN ELECTRONIC CONTROL MODULE IGNITION 1 HEATER DESCRIPTION INJECTORS INSTRUMENT PANEL LAMPS WINDSHIELD WIPERS FUSE BLOCK GASOLINE ENGINE W/AUTO TRANS B-11 -8-1.0 GRAA A“TA a a i a 0; m GU 1) a □ ACC □ a-B □s m a n □ a n l\ £ & b o 350-.8 PNK/WHT - FUEL CYC MDL- m □ □ IGN HTR PWR 0 d 0 nr I ii 0 in F I i n i 240-1.0 ORN - HORN RLY • DOME LAMP SHUNT 12041235 8-.8 GRA - INSTRUMENT LAMPS 8-1.0 GRA -------------------------------------------- □ q ' t ! □ tfe A i □ □ Okfl m IB □□ w I DPWRJP — 50-3.0 BRN □ □ [ID 0 □ □ □ -141-1.0 BRN/WHT 4-5.0 BRN - IGN SW 93-3.0 WHT - WINDSHIELD WIPER 16-.8 PPL - TURN SIGNAL SW 75-.8 DK BLU - BACK-UP LAMP SW Pel ■44-1.0 DK GRN - LT SW RHEOSTAT .40-1.0 ORN - TAIL LAMPS [ I/© i □ ski 1 I k s -140-1.0 ORN - STOP LAMP SW - HAZ FLSHR □0 -3-5.0 PNK - IGN SW - ENG IGN -39-.8 PNK/BLK - INSTRUMENT CLUSTER □ □ B<1 -39-1.0 PNK/BLK - ALTERNATOR - EGR SOLENOID REAR FRONT 12034359 - BLOCK MOLD 12089774 - PRINTED BLOCK 38-.8 DK BLU - TURN SIGNAL- COLOR MALE CONN BRN 12004887 B BLK 12004886 H GRN 12004885 I NAT 12004888 L BLU 12004884 A B-12 FUSE BLOCK DIESEL ENGINE W/MAN TRANS FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION ACC-RADIO 12004007 RED 10 AMP HOT IN ACC OR RUN ALT 12004009 YELLOW 20 AMP HOT IN RUN OR START GAUGES 12004009 YELLOW 20 AMP HOT IN RUN HORN-DM 12004008 LT BLUE 15 AMP HOT AT ALL TIMES HTR 12004010 WHITE 25 AMP HOT IN RUN DESCRIPTION FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION RADIO ACCESSORIES INSTR-LPS 12004005 TAN 5 AMP HOT W/ HEADLAMP IN PARK OR HEAD ALTERNATOR STOP-HAZ 12004008 LT BLUE 15 AMP HOT AT ALL TIMES STOP LAMPS HAZARD FLASHER PROVISIONS FOR QAQES TAIL LPS 12004009 YELLOW 20 AMP HOT AT ALL TIMES TAIL LAMPS PROVISIONS FOR HORN AND DOME LAMPS TURN-B/U 12004008 LT BLUE 15 AMP HOT IN RUN OR START WIPER 12004010 WHITE 25 AMP HOT IN ACC OR RUN HEATER DESCRIPTION INSTRUMENT PANEL LAMPS TURN SIGNALS BACK-UP LAMPS WINDSHIELD WIPERS 8-1.0 GRA 240-1.0 ORN - HORN RLY - DOME LAMP SHUNT 12041235 8-.8 GRA - INSTRUMENT LAMPS 8-1.0 GRA---------------------------------------------- 44-1.0 DK GRN - LT SW RHEOSTAT 40-1.0 ORN - TAIL LAMPS 140-1.0 ORN - STOP LAMP SW - HAZ FLSHR 439-1.0 PNK/BLK - ECM (FUSED) 16-.8 PPL - TURN SIGNAL SW 75-.8 DK BLU - BACK-UP LAMP SW 3-5.0 PNK - IGNITION 3-5.0 PNK - IGN SW - ENG IGN 39-.8 PNK/BLK - INSTRUMENT CLUSTER 39-1.0 PNK/BLK - ALTERNATOR - EGR SOLENOID 38-.8 DK BLU - TURN SIGNAL- COLOR MALE CONN A BRN 12004887 B BLK 12004886 H GRN 12004885 1 NAT 12004888 L BLU 12004884 FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION ACC-RADIO 12004007 RED 10 AMP HOT IN ACC OR RUN RADIO ACCESSORIES ALT 12004009 YELLOW 20 AMP HOT IN RUN OR START ECM-BAT 12004007 RED 10 AMP HOT AT ALL TIMES ECM-CRNK 12004007 RED 10 AMP HOT IN RUN OR START GAUGES 12004009 YELLOW 20 AMP HOT IN RUN HORN-DM 12004008 LT BLUE 15 AMP HOT AT ALL TIMES DESCRIPTION FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION HTR 12004010 WHITE 25 AMP HOT IN RUN ALTERNATOR INSTR-LPS 12004005 TAN 5 AMP HOT W/ HEADLAMP IN PARK OR HEAD ELECTRONIC CONTROL MODULE STOP-HAZ 12004008 LT BLUE 15 AMP HOT AT ALL TIMES TRANS 142004007 RED 10 AMP HOT IN RUN OR START PROVISIONS FOR GAGES TAIL LPS 12004009 YELLOW 20 AMP HOT AT ALL TIMES PROVISIONS FOR HORN AND DOME LAMPS TURN-B/U 12004008 LT BLUE 15 AMP HOT IN RUN OR START TURN SIGNALS BACK-UP LAMPS WIPER 12004010 WHITE 25 AMP HOT IN ACC OR RUN WINDSHIELD WIPERS ELECTRONIC CONTROL MODULE IGNITION 1 DESCRIPTION HEATER INSTRUMENT PANEL LAMPS STOP LAMPS HAZARD FLASHER TRANSMISSION TAIL LAMPS FUSE BLOCK DIESEL ENGINE W/AUTO TRANS B-13 LAMP BULB DATA AC Type Guide Lamps are recommended when replacement becomes necessary. Lamp Usage Headlamp1 Quantity 2 Trade No. Power Rating at 12V, Watts 6014 50/60 W Candle Power Park and Signal Lamp2 2 2057 32-2 Tail and Stoplamp3 (Union City Body Co.) 2 1157 32-3 Tail and Stoplamp2 (Except Union City Body Co.) 2 2057 32-2 Front Side Marker Lamp 2 194 2 Rear Side Marker Lamp 2 194 2 License Lamp 2 67 4 Backup Lamp4 — — — Instrument Cluster Illumination Lamp 6 PC194 2 Turn Signal Indicator Lamp 2 PC194 2 Headlamp High Beam Indicator Lamp 1 PC74 .7 Service Brake Warning Indicator Lamp 1 PC74 .7 Park Brake Warning Indicator Lamp 1 PC74 .7 Transmission Control Illumination Lamp 1 73 .3 Low Coolant Indicator Lamp5 1 PC74 .7 Glow Plug Indicator Lamp5 1 PC74 .7 Water in Fuel Indicator Lamp5 1 PC74 .7 Service Engine Soon Indicator Lamp 1 PC74 .7 Trans Indicator Lamp5 1 PC74 .7 Fasten Safety Belts Indicator Lamp6 1 PC74 .7 Door Ajar Indicator Lamp 1 PC74 .7 Daytime Running Lights Indicator Lamp7 1 PC118 .7 1. 2. 3. 4. 5. 6. 7. B-14 BULB DATA Double filament sealed beam: 50W low beam, 60W high beam. Double filament lamp: 32 CP high, 2 CP low. Double filament lamp: 32 CP high, 3 CP low. Refer to body manufacturer’s specifications. Diesel only. When used by body manufacturer. Canada only. & < z RH HIGH-LOW HEADLAMP (SEE PAGE 23) LH HIGH-LOW HEADLAMP (SEE PAGE 23) [ 150-.8 BLK ■ (DRIVEAWAY ONLY) 150-.8 BLK | (DRIVEAWAY ONLY) z 0 1 > d o ! tr o ■COPPER BRAID i & ENGINE GROUND G110 SHEET METAL GROUND G111 FRAME GROUND G106 SHEET METAL GROUND G107 SHEET METAL GROUND G105 FRAME GROUND G104 SHEET METAL GROUND G106 SHEET METAL GROUND G105 FRAME GROUND G104 ENGINE GROUND G120 DASH PANEL GROUND G121 GROUND DISTRIBUTION FORWARD LAMPS B-15 . ._ _ _ _ _ _ _ _ _ _ _ 486-.8 BRN rI II r" -----CC 450-.8 BLKlWHT - -~ 450-.8 BLKlWHT - . . - ESC HYBRID FUNCTION (SEE PAGE 44) EVRV (L05 ONLy) (SEE PAGE 46) FUEL PUMP RELAY (SEE PAGE 54) II II r I ".-_.'mKIW""_ - - - - - '"'' ~ ....... """""'- + i "-450-.8BLKlWHT _ _ - - - - - - -_ ,\''t '~_450-.8BLKlWHT_ , • \ \... •i ,, ~ ~ I J - -.r - - - """""' -GROUND DISTRIBUTION GASOLINE ENGINE WIMAN TRANS - ECM (SEE PAGE 45) .... DRAC (SEE PAGE 64) ... 450-.8 BLKlWHT _ .... ECM (SEE PAGE 45) . - 450-.8 BLKlWHT _ ... ALDL (SEE PAGE 45) 450-.8 BLKlWHT - ..-450-.8 BLKlWHT ___ GT100 12020107 (UPPER) 12020708 (LOWER) ~_ _ 413-.8 TAN ,,t ,, ,, , \ ALTERNATOR BRACKET GROUND G101 B-16 - --, - - ...., m C! I - ...-.c - -.r - - - - - - -=- ENGINE GROUND G100 ----lICe ECM (SEE PAGE 45) , ~ "..., ...., - , -, r , , 450-.8 BLK/WHT ~ 450-.8 BLK/WHT • FUEL PUMP RELAY - ...., - - ...... I(SEE PAGE 54) --c - EIIRV (L05, L19) (SEE PAGE 46) I I ,I ,I ,. , - ... 450-.8 BLK/WHT.......... 450-.8 BLK/WHT - - - "..., - - - "..., - "..., - VI:~-~"~~- S102 "..., ... 450-.8 BLK/WHT ~ • If _ t, , , ~_ - , , DRAC (SEE PAGE 64) "..., - ...., , ., , ) , I ~- ALTERNATOR BRACKET GROUND G101 ~ - ... 450-.8 BLK/WHT.... - - - ....... - -- - - 551-.8 TAN/WHT " . . . , ..... PCM (SEE PAGE 51) ;~~ PAGE 51) GT100 , , \.. ,- -.,.,""""'- -1 " " i ', * ~ ,...., - ~"'-"''''_'''O"'~-.- - ,~ , " ALDL (SEE PAGES 45, 47) 120201071UPPER) 120201081LOWERI C . ._ _ 413-.8 TAN - - - -. . . PCM (SEE PAGE 51) ' , '' ' l ; ,, ,~ '. , i , ~ '"' ENGINE GROUND G100 GROUND DISTRIBUTION GASOLINE ENGINE W/AUTO TRANS B- 17 RPO CODES L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K T61 ■ CANADIAN DAYTIME RUNNING LAMPS l/P CLUSTER CONNECTOR (SEE PAGE 70) l/P GROUND G200 B-18 GROUND DISTRIBUTION GASOLINE ENGINE RPOCODES T61 - CANADIAN DAYTIME RUNNING LAMPS . .- _ _ _ _ _ _ 150-3.0 BLK _ PANEL DIMMER SWITCH (SEE PAGE 72) ....I ~ 0 () 150-.8 BlK 150-.8 BlK --C 150-.8 BlK --II DRAC (SEE PAGE 65) 150-.8 BlK --C lOW COOLANT MODULE (SEE PAGE 70) 150-.8 BlK --C liP C . ._ _ _ _ 150-.8 BLK - - - -. . . ~_ _ _ _ 150-.8 BlK -----CC FUEL HEATER (SEE PAGE 63) WATER IN FUEL SENSOR (SEE PAGE 63) = Cl D A J B 150 39 C 3 419 0 2 31 E 439 35 F G 2 440 H 6 K L M N ~1 2 PARK BRAKE SWITCH (SEE PAGE 70) 3 5 0 Cl ~_ _ WIPER SWITCH (SEE PAGE 38) Cl00 12020184 , C " '_ _ _ _ 150-.8 BlK - - - -. . GLOW PLUG CONTROllER (SEE PAGE 61) ENGINE DRl RELAY (T61) (SEE PAGE 27) '-_ ' -_ _ _ _ 150-1.0 BlK I [, I 6 1250148111 H I 440 1470 1 824 \I G I 2 I 1ltD "" ~ F E 439 35 1 I I I 311 ~@ 1m -.: \ 419 1 I 39 11111 I 1120 I 1 2 3 150 I 1 150-.8 BlK _ _ DRl MODULE (T61) (SEE PAGE 27) = IS2I ~ 15O-.8BlK --II 150-.8 BlK --C 1 2 3 0 C B ? A 129 = liP CLUSTER CONNECTOR Cl00 12020183 -ENGINE GROUND G100 (SEE PAGE 70) 150-.8 BlK --C 150-.8 BlK --C liP GROUND G200 GROUND DISTRIBUTION DIESEL WIMAN TRANS B-19 ,..-.. ,, ,, RPOCODES ~ ~ ..-.. ...-r ,..-.. ,, ,, ,, , ,, ,, ,, ,, ,, ,, ,, ,, ~- ENGINE GROUND G102 B-20 S114 ~ .... 551-.8 TAN/WHT 551-.8 TAN/wHT ... . . - . ....... TCM (SEE PAGE 58) "450-.8 BLKlWHT ~....c ~ ...- 450·.8 BLKlWHT'" T61 - CANADIAN DAYTIME RUNNING LAMPS TCM (SEE PAGE 58) . .- - - - 150-3.0 B L K " . ._ _ _ _ 150,.8 BLK _ _. . 150'.8 BlK ( ALDl (SEE PAGE 57) 150-.8 BLK ( DRAC (SEE PAGE 65) PANEL DIMMER SWITCH (SEE PAGE 72) GT100 . ._ _ 150-.8 BLK _ _. . 12020107 (UPPER) 12020108 (LOWER) . .- - - - - - - - - - - 150-.8 BlK ------------l1li(( 150-.8 BlK.... 150-.8 BlK.... FUEL HEATER (SEE PAGE 63) 50-.8 BlK _ _ _ _ _ _ _ _ _ _ _ _. (. 1 WIPER SWITCH (SEE PAGE 38) WATER IN FUEL SENSOR (SEE PAGE 63) .1________________ '50-.8 Bll(" lOW COOLANT WARNING MODULE (SEE PAGE 70) 150-.8 BlK.... 11_ _ _ _ _ _ _ _ _ _ _ PARK BRAKE SWITCH (SEE PAGE 70) ------------1(( DRL RELAY (T61) (SEE PAGE 27) S203 DRl MODULE (TS1) (SEE PAGE 27) GLOW PLUG CONTROLLER (SEE PAGE 61) 150-.S BLK _ _ ' -_ _ _ _ _ _ _ _ _ _ _ 150-.SBlK _ _ _ _ _ _ _• 150-.S BLK _ _ . .- - - - -_ _ _ _ 150-.S BlK _ _. . lIP CLUSTER CONNECTOR (SEE PAGE 70) Cl C100 12020183 = E!J 3 ENGINE GROUND G100 GROUND DISTRIBUTION DIESEL W/AUTO TRANS = D 0 A 2 B 150 39 C 0 3 2 31 E 439 35 F 2 G 440 420 H 6 250 ~1 --- 150-.BBlK . . . . 9 11 l 12 M 9 Di::;;;;;:;;;;;:J0Cl lS0-.SBlK· . . . . N 5 = Cl00 12010184 ENGINE I:I~:~~ 29 3 2 ~ --lIP GROUND G200 ~.!IJi!t;.------- . ._ _ _ 150-1.0 BLK _ _ _ _ _ _.~'" 150-.8 BLK - - - - • S404 r C 150-.8 BLK - -. . . "" - 150-.8 BLK ---C. PROVISIONS FOR RH SIDE MARKER (SEE PAGE 76) PROVISIONS FOR LH SIDE MARKER (SEE PAGE 76) 12065158 -- FRAME GROUND G400 C402 12034342 --- SHEET METAL GROUND G402 GROUND DISTRIBUTION REAR B-21 CIRCUIT OPERATION LOW BEAM LAMP(S) DO NOT OPERATE TEST Voltage is applied to the Light Switch at all times. The Light Switch includes a Self-Resetting Circuit Breaker. The Circuit Breaker opens when the Light Switch circuit draws too much current. When the Circuit Breaker opens, it interrupts the current flow. With no current flow, the Circuit Breaker cools off and resets automatically. When the Light Switch is in HEAD, the Dimmer Switch directs voltage to either the Low Beams or the High Beams. The HI Beam Indicator also receives voltage along with the High Beams. RESULT 1. Turn light switch ON and headlamp dimmer switch to LOW BEAM position. Connect a test lamp from TAN (12) wire at connector C100 to ground. Test lamp does not light. GO to step 2. Test lamp lights. ISOLATE problem in body builder’s installed wiring. 2. Connect test lamp from TAN (12) wire at headlamp dimmer switch connector C210 to ground. Test lamp does not light. GO to step 3. Test lamp lights. LOCATE and REPAIR open in TAN (12) wire from headlamp dimmer switch connector C210 to connector C101. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C210 to ground. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire from headlamp dimmer switch connector C210 to light switch connector C209. Test lamp lights. REPLACE headlamp dimmer switch. DIAGNOSIS - HEADLAMPS HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS » BOTH SIDES ACTION RESULT TEST 1. 2. 3. Connect a test lamp from RED (2) wire at light switch connector C209 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from light switch connector C209 to battery junction block. With the light switch on and the dimmer switch to HIGH BEAM, connect a test lamp from YEL (10) wire at light switch connector C209 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C210 to ground. Test lamp lights. 3. HIGH BEAM LAMP(S) DO NOT OPERATE TEST 1. Test lamp does not light. REPAIR open in LT GRN (11) wire from headlamp dimmer switch connector C210 to connector C100. REPLACE headlamp dimmer switch. 2. 3. B-22 HEADLAMPS BASE ACTION Place light switch to ON and dimmer switch to HIGH BEAM position. Connect a test lamp from LT GRN (11) wire at connector C100 to ground. Place headlamp dimmer switch in HIGH BEAM position. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C210 to ground. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C210 to ground. RESULT ACTION Test lamp does not light. GO to step 2. Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. GO to step 3. Test lamp lights. LOCATE and REPAIR open in YEL (10) wire at headlamp dimmer switch connector C210 to light switch connector C209. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire at headlamp dimmer switch connector C210 to light switch connector C209. Test lamp lights. REPLACE headlamp dimmer switch. JUNCTION BLOCK S197 HEADLAMP DIMMER SWITCH C210 8917693 BASE HEADLAMPS WIRING B-23 0 RH SIDE MARKER LAMP 1iL| VJJ HORN C145 ®L47 12077765 T 115-.5 DK BLU | .• S121 NOTE: This harness is shipped along with the vehicle and is installed by the body builder. LH SIDE MARKER LAMP G106 B-24 FORWARD LAMP HARNESS G107 SHEET METAL GROUND G105 12077765 FRAME Q / GROUND G104 CIRCUIT OPERATION LOW BEAM LAMP(S) DO NOT OPERATE TEST CANADIAN DAYTIME RUNNING LAMPS the DRL Indicator in the Instrument Panel and energizes the DRL Relay. When energized, the DRL Relay disconnects the LT BLU/ORN (593) wire from ground and internally connects it to the LT GRN/BLK (592) wire causing it to be 12 volts. Battery voltage is applied to the Daytime Running Lamps (DRL) Module from the BRN (50) wire and the HTR fuse. With the Headlamps on, the DRL Relay is not energized and the LT BLU/ORN (593) wire is grounded to BLK (150) wire inside of the relay. This serves as ground for the LH Headlamp. The LT BLU/ORN (593) wire feeds the LH High beam which is connected in series to the RH Headlamp through the LT GRN (11) wire. Grounding of the entire DRL circuit is accomplished through the BLK (151) wire at the RH Headlamp. This results in High beam headlamps that are less intense for daytime driving and should provide longer service. With Ignition in RUN, headlamps off and Parking Brake released, the DRL Module applied battery voltage to the LT GRN/BLK (592) wire. This action illuminates RESULT 1. Turn light switch ON and dimmer switch to LOW BEAM position. Connect a test lamp from TAN (12) wire at connector C100 to ground. Test lamp does not light. GO to step 4. Test lamp lights. GO to step 2. 2. Test lamp does not light. LOCATE and REPAIR open in LT BLU/ORN (593) wire from light connector C100 to DRL relay connector C243. Test lamp lights. GO to step 3. Connect a test lamp from BLK (150) wire at the DRL relay connector C243 to ground. Test lamp does not light. REPLACE DRL relay. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire from DRL relay connector C243 to ground G200. If not open is found, ISOLATE problem in body builder’s installed wiring. Connect a test lamp from TAN (12) wire at headlamp dimmer switch connector C210 to ground. Test lamp does not light. GO to step 5. Test lamp lights. LOCATE and REPAIR open in TAN (12) wire from connector C100 to headlamp dimmer switch connector C209. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C210 to ground. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire from headlamp dimmer switch connector C210 to light switch connector C209. Test lamp lights. REPLACE headlamp dimmer switch. 3. Connect a test lamp from LT BLU/ORN (593) wire at DRL relay connector C243 to ground. DIAGNOSIS - HEADLAMPS (WITH DRL) PRELIMINARY CHECKS: Lamp(s) are inoperative, refer to the HIGH BEAM LAMP(S) DO NOT OPERATE test procedures. If the High Beam Lamp(s) are operative, use the following diagnostic procedures, after placing the Light Switch to OFF position. Before checking the DAYTIME RUNNING LAMPS system, do the following: 1. Place Park Brake in the OFF position. 2. Place Light Switch to ON and Headlamp Dimmer Switch to HIGH BEAM position. If the High Beam HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS - BOTH SIDES TEST 1. 2. 3. ACTION RESULT Connect a test lamp from RED (2) wire at light switch connector C209 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from light switch connector C209 to fuse block. Connect a test lamp from YEL (10) wire at light switch connector C209 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C210 to ground. Test lamp lights. REPAIR open in LT GRN (11) wire from headlamp dimmer switch connector C210 to connector C100. Test lamp does light. REPLACE headlamp dimmer switch. ACTION 4. 5, CANADIAN DAYTIME RUNNING LAMPS (DRL) B-25 CANADIAN DAYTIME RUNNING LAMPS DO NOT OPERATE HIGH BEAM LAMP(S) DO NOT OPERATE TEST 1. 2. TEST ACTION RESULT Connect a test lamp from LT GRN (11) wire at connector C100 to ground. Test lamp does not light. GO to step 4. Test lamp lights. GO to step 2. Connect a test lamp from LT BLU/ORN (593) wire to ground at DRL relay connector C243. Test lamp does not light. LOCATE and REPAIR open in LT BLU/ORN (593) wire between connector C100 and DRL relay connector C243. 1. With ignition in RUN, headlamps off and park brake released, connect a testlamp from ORN (240) wire at DRL relay connector C242 to ground. 2. 3. 4. 5. Connect a test lamp from BLK (150) wire at DRL relay connector C243 to ground. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C210 to ground. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C210 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE DRL relay. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire from DRL relay connector C243 to ground G200. Test lamp does not light. GO to step 5. Test lamp lights. LOCATE and REPAIR open in LT GRN (11) wire from connector C100 to headlamp dimmer switch connector C210. Test lamp does not light. Test lamp lights. LOCATE and REPAIR open in YEL (10) wire at headlamp dimmer switch connector C210 to light switch connector C209. 3. 4. REPLACE headlamp dimmer switch. 5. B-26 CANADIAN DAYTIME RUNNING LAMPS (DRL) Connect J 34029-A Multimeter from BRN (50) wire at DRL module connector C243 and DRL relay connector C242 to ground. Measure voltage. Connect J 34029-A Multimeter from B R N (50) wire at DRL module connector C243 and DRL relay connector C242 to BLK (150) wire at each component connector. Measure voltage. Connect J 34029-A Multimeter from LT GRN/BLK (592) wire at DRL relay connector C242 to ground. Measure voltage. Connect a test lamp from LT BLU/ORN (593) wire at connector C101. RESULT ACTION Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire between DRL relay connector C242 and fuse block. If no open is found REPLACE DRL fuse. Test lamp lights. GO to step 2. Battery voltage at only one connector. LOCATE and REPAIR open in BRN (50) wire between splice S212 and connector with missing voltage. No battery voltage at either connector. LOCATE and REPAIR open in BRN (50) wire between splice S212 and fuse block. If no open is found, REPLACE HTR fuse. Battery voltage at both connectors. GO to step 3. No voltage. LOCATE and REPAIR open in BLK (150) wire between suspect connector and ground G200. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in LT GRN/BLK (592) wire between the DRL relay and the DRL module. If no open is found, REPLACE DRL module. Battery voltage. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in LT BLU/ORN (593) wire between DRL relay connector C242 and connector C100. If no open is found, ISOLATE problem in body builder’s installed wiring. Test lamp lights. Daytime running lamps are operational. RH SIDE MARKER LAMP ~ RH HIGH-LOW HEADLAMP ~ ~" C145 12077765 _ _ _ 11-H) LTGRN 11 12 C137 12004267 151 z a: to C144 2973386 ~ -I . ._ _ _ _ _ _ 151-.8BLK _ _ 15-.8 OK BLU_ d> _ _15-.50KBLU _ _ _ _ _ _ _ _ __ _ . _ _ _• 15-.8 OK BLU 8124 z a: :.:: l!l RH PARK AND TURN LAMP - '--~-i'. BLK~ .,8 C143 2984855 0 _______ • 0 8121 r~.'" I , ------, I :, ,, ------,, ~ z a: 1--.. . CO Ll) 8123 14-.8LTBLU _ _ LH PARK AND TURN LAMP '--~~....,.8 - . ---. '" ·8·12·2-- 9-.8 BRN - - - - - - - - - 12-.8TAN _ _ _ _ _ _. . ~ C101 12020100 12-.8 TAN - - 11 12 r I- 29·~11 C> to 1H.OLTGRN _ _ _ __ ... . . . , AI 593-.8 OK BLU/WHT r 9 .. ,I S z '"ch 2973386 11 12 ill~ 593 15 z a: o C140 • 1- .., l!l l!l 150 • ~ 1- 1'3 a: z a: S LH HIGH-LOW HEADLAMP "WWHO' _14-.8 LT BLU -9-.8BRN 14-.5 LTBLU i - BLKL® C142 2984855 Cd> N ~ ..oj r . . . , .. --- ~ --------~ . . . , . . . , . . . , . . . , .. r . . . , . . 593-.80KBLU/WHTr ~ ..., ~ 151-3.0 BLK LH SIDE MARKER LAMP C141 12077765 o - G105 SHEET METAL GROUND -- NOTE: This harness is shipped along with the vehicle and is installed by the body builder. FRAME GROUND G104 FORWARD LAMP HARNESS W/DRL 8-27 JUNCTION BLOCK HTR 25 AMP HORN/OM 15 AMP ~ 1·------------------------.R.O.E.~·L·y--50-3.08AN - - . ~ ~ ~--. 50-3.0 8AN - - - _ _ _ _ ... ~---2-1.0R8T-------. ~ (FU818LE LINK) . ._ _ _ _.240-1.0 DAN _ _ _ _ _ _ _ _ _ _ • 8197 8298 (8EE PAGE 36) 5O-3.08AN _ ~ 8212 • _ 592-.8LTGAN/8LK _ _ ~ 50-3.0 8AN _ _ _ _ _...~ C243 12052287 . ._ _ _ _ _ _ _ _ _ _ 240-.8 DAN _ _ _ _ _ _ _ _ _ _• ..J , . ._ _ _ _ _ _ _ _ _ 150-.8 8LK _ _ _ _ _ IIj.~ := o u oW C100 12020183 ENGINE 0:: o ~ lS = e2J A B C 3 R G H = ~ Z 0:: 2 ~ 1 m 1'20 1 1340 I I 33 I 39 1450 I OJ 14191 3 I ~~@~ " .... . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ _ _ _ _ _ 12-.8TAN _ _ _ _ _........ UP I 31 1 2 135 1439 I I 2 II I 1440 I 11143419061 6 I ~ VVVV\\VVWVM 40 1 ORN 140-1.0 TAIL LPS: TAIL LPS 5 20 20 AMP AMP PANEL DIMMER SWITCH - ,OORN - - - - - - - - - - - - - - - . 44 —K A B c ° n M l i 1 5 0 1 156 j 44 j L L ^ i —'Li’------ — 1 C297 12020030 9-,8 BRN LIGHT SWITCH 150 ---;r----e 156 DOME 2 CIRCUIT \PARK , BREAKER 25AMP 10 HEAD \ 40-1-_'-; OFF 'PARK 9 LIGHT SWITCH . ._ _ _ _ _ _ _ 40-1,OORN_-II-_ _ _ REAR BODY CONNECTOR 6 5 4 REAR LAMP HARNESS zII: III q A 340 B 450 C 3 D 2 E 439 Z II: III q m F G 440 H 6 ~1 Cl00 12020184 FRAME GROUND (O ) G400 - ■ "= PARK AND MARKER SIGNAL LAMPS 8 ..31 B-31 STOP-HAZ 15 AMP _ P I I - - - - - - - - · 1 4 0 - 1 . 0 0 R N - - - - - - - - -• ........_ _ _ _ _ _ _.140-1.0 ORN _ _ _ _ _ _ _ _ _ _ _ .1 ,-- - . ,.. ... - (STEERING COLUMN SWITCHES) , ,_ _ _ _ 17-1.0 WHT ---------..J.F::U __ __ __ .19-1.0 GRRIN::.:::::::::I~~ _ 18-1.0 DK YEL • , . . . . . 15-.5 DK BLU • --------~w=lIJr _ _ _ 14-.5LTBLU_ P .L..:.:......I1..-1.O WHT ---------_-+_~~_-+-I.-----.... 1.0 DK GRN N -1..+-.3 1.0 YEL _ _- . - - - - - -_ _ M L .8 PPL K 1.0 BRN +-_-+__ J H .5 LT BLU - - - - - - - - G .5 BLK - - - - - - - - - . a: o C! ~ F E 0 HORN z ~q ~q ffi PRNDL LAMP .........- - .5 GRA (SEE PAGE 72) BLU _ _ _ _ _ _ _. . . 14-.5 LT ~ r-!. ~ REAR LAMP HARNESS KEY C206 12004147 a: m z TURN SIGNAL SWITCH ~ BLU _ _ _ _ _ _. . . NORMALLY OPEN SWITCHES lIP CLUSTER CONNECTOR ~ ..J 15-.5 DK 3: 0 0 (SEE PAGE 70) 18-2.0YEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. -. . . . . . . . . . . . . .. -. . . 5 6 ~ItIeL K /~ 1 t~ )\. ,~ .. • • '«:' 18 19 30 241 I~ liP ~l....r~ 19-2.0 DKGRN ........- - - - - - -...- -...............- ......- -...- -...- REAR BODY CONNECTOR C 102 12020099 '" 340 B 450 39 C 3 419 0 2 31 E 439 35 I' 2 G 440 H 6 ~1 120 33 :J I! III 93 III 906 434 11 \J 2 0 3 STOPLAMP SWITCH (CLOSES WHEN BRAKE PEDAL IS DEPRESSED) J III! 340 18 9 IQ) , r 94 ~ " ..., A "'"- 9 120 19 K 11 L 12 M 15 593 14 29 v 6 D 5 9 N 2984235 P 4r:Sf/ ClOO 12020184 27-1.0 BRN 17-1.0WHT B , 140-1.00RN ~o' ~_ "'A::,=::27-1.0 BRN _ _ _ _ _ _1 ~ C228 2973385 HAZARD FLASHER 8-32 HAZARD SIGNAL LAMPS I I ...- ......... . - TURN SIGNALS DO NOT WORK ON ONE SIDE CIRCUIT OPERATION TEST TURN SIGNAL LAMPS With the Ignition Switch in RUN or START, voltage is applied through the TURN/BU Fuse and Turn Flasher to the normally closed contact of the Hazard Flasher Switch in the Turn Signal Switch. Lamp will find a path to ground through Splice S123 and the Park and Turn Lamp to ground. This Lamp provides low resistance paths to ground. The Marker Lamps will flash with the Turn Lamps. With the Turn Signal Switch in LH Turn position, voltage is applied to both the LH Turn Indicator and the LH Front Park and Turn Lamp LT BLU (14) wires. Voltage is applied to the LH Tail, Stop and Turn Lamp YEL (18) wire. When the Light Switch is in either PARK or HEAD, voltage is applied through the TAIL LPS Fuse, Lamp Switch, and Splice S122 to the Marker and Park Lamps. If the Turn Signal Switch is in TURN LEFT, the LH Side Marker Lamp will have voltage at both connections and will go out. When the Flasher removes voltage to the Turn Lamp, the Marker Lamp will be grounded through the Turn Lamp and will go on. In this way, the LH Side Marker Lamp will flash on when the LH Park and Turn Lamp goes off, and off when the Turn Lamp goes on. The Lamps go on immediately. They begin to flash when the current flow heats up the Timing Element in the Flasher and it repeatedly opens and closes the circuit. The voltage applied to the LH Park and Turn Lamp will also be applied to the LH Side Marker Lamp. If the Lamp Switch is in the OFF position, the LH Side Marker With the Turn Signal Switch in TURN RIGHT, voltage will be applied to the RH Lamps in the same way. DIAGNOSIS - TURN LAMPS RESULT 1. Turn hazard warning system on. Observe lights on side of turn signals that did not work. Lights flash. CHECK for improper bulb. REPLACE if necessary. Lights do not come on. GO to step 2. Test lamp lights. GO to step 4. Test lamp does not light. GO to step 3. Connect test lamp from PPL (16) at turn signal switch connector C206 to ground. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. REPLACE turn signal flasher. Connect test lamp from LT BLU (14) or DK BLU (15) wire (depending on which side did not work) at park and turn lamp connector C142 or C143 to ground. Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. LOCATE and REPAIR open in either LT BLU (14) or DK BLU (15) wires between turn signal switch connector C206 and connector C100. 2. Turn hazard warning system off. Place ignition switch to RUN and turn signal to side that does not work. Connect test lamp from LT BLU (14) or DK BLU (15) wire (depending on which side does not work) at turn signal switch connector C206 to ground. 3. 4. ACTION TURN SIGNALS DO NOT OPERATE TEST 1. Place hazard warning lamps to on position. 2. Connect a test lamp from PPL (16) wire at turn signal switch connector C206 to ground. RESULT ACTION Hazard lamps operate. GO to step 2. Hazard lamps do not operate. REFER to "Hazard Lamps Do Not Operate" symptom. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. CHECK condition of TURN/BU fuse and an open in PPL (16) wire or DK BLU (38) wire. If fuse and wiring are good, REPLACE turn signal flasher. TURN SIGNAL LAMPS FLASH RAPIDLY TEST Turn hazard lamp switch ON. Check front signal lamps and rear taillamps. RESULT ACTION One side of turn signal lamps flash rapidly. REPLACE inoperative turn signal bulb. Only one side of turn signals light but do not flash rapidly. REFER to "Turn Signals Do Not Work On One Side" symptom. TURN SIGNAL LAMPS B-33 FUSE BLOCK (STEERING COLUMN SWITCHES) 12103404 £Al ~ L [IJ:ITl (BJ 0 (BJ 0 L lID lID 00 [IJ:ITl lIDlIDOODITlDD ACC IGN HTR PWR 000000 ~ 17 19 18 K 27 27-1.0 BRN J 15 15-.5DKBLU~ [AJ [jUGB HORN/OM INSTR-LPS INJ 16 17-1.0 WHT 19-1.0DKGRN _ _ 18-.8 YEL lS-.8 PPL TRANS TURN SIGNAL SWITCH I ~~oo TAIL LPS P N M L I H HTR s~E~:LOA~~ G o D 14-.5 LT BLU 28-.5 BLK I I ~ F E OO~ ~ Pu::D HORN C20S 12004147 • KEY ~~~--~~.I ~ '-+-~-..., ~ I NORMALLY OPEN SWITCHES PRNDL ~ 8-.5 GRA LAMP (SEE PAGE 72) BACKUP _ _...~ LAMP SWITCH (SEE PAGE 78) z a: ..J W (!) . ._ _ _ _ _ _ _ _ _ _ _ _ _ 14-.5 LTBLU _ _ _ _ _ _ _ _ _ _ _... ~ ~ >- 0 ~ ~ a, cJ, . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ 15-.5 DKBLU _ _ _ _ _ _ _ _ _ _ TURN FLASHER ~.~ liP CLUSTER CONNECTOR (SEE PAGE 70) 3 :3 ~ o 10 .h w ':J 10 ± 14 29 6 5 3 2 DOt::;;;;;;;::JO::J = Cl00 12020184 8-34 TURN SIGNAL LAMPS Cl02 12020099 12065158 CIRCUIT OPERATION When the Horn Switch is depressed, one side of the coil of the Horn Relay is grounded. The relay is energized. Its contacts close and battery voltage is applied to the Horn. DIAGNOSIS - HORNS PRELIMINARY CHECKS: Check to see that the HORN D/M fuse is not blown. REPLACE if blown. HORN(S) W ILL NOT OPERATE TEST 1. Connect a test lamp from DK GRN (29) wire at connector C100 to ground. Press horn switch. 2. 3. 4. RESULT ACTION Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. GO to step 2. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire between horn relay connector C207 and fuse block. Install horn relay. Disconnect turn signal switch connector C206. Use a jumper wire to ground BLK (28) wire at turn signal switch connector C206. Horn does not sound. GO to step 4. Horn sounds. REPLACE horn switch. Disconnect horn relay. Install a jumper wire from ORN (240) terminal to DK GRN (29) terminal at horn relay connector C207. Horn sounds. REPLACE horn relay. Horn does not sound. LOCATE and REPAIR open in DK GRN (29) wire from horn relay connector C207 connector C100. Remove horn relay. Connect a test lamp from ORN (240) wire at horn relay connector C207 to ground. HORN SOUNDS CONTINUOUSLY WITHOUT DEPRESSING HORN SWITCH RESULT TEST 1. 2. Disconnect turn signal switch connector C206. Disconnect horn relay connector C207. ACTION Horn stops. REPLACE horn switch. Horn continues to sound. GO to step 2. Horn stops. REPLACE horn relay. Horn continues to sound. LOCATE and REPAIR open in BLK (28) wire between horn relay connector C207 and horn switch. HORN B-35 S HOT A T A L L TIM ES C HORN/DM 15 AMP 240-1.0 ORN I HORN RELAY 28-.5 BLK z PRNDL LAMP ^ (SEE PAGE 72) CL O TURN SIGNAL SWITCH § O O S298 240-.8 ORN 340 120 ! 450 39 3 419 2 31 439 35 2 440 6 33 J % ( r n 906 434 <=c B-36 HORN PROVISIONS FOR DOME LAMPS (SEE PAGE 38) 240-.8 ORNl WIPERS DO NOT OPERATE IN LO CIRCUIT OPERATION TEST WIPER is through the PPL wire, the Wiper/Washer Switch and the BLK wire to ground. The Wiper Motor is supplied battery voltage with the Ignition Switch in START or RUN, with ground supplied by the Wiper/Washer Switch. 1. RESULT Place ignition in RUN and wipers to LO. Connect a fused jum per from GRA (91) wire at wiper switch connector C221 to ground. ACTION Wiper m otor does not run. LOCATE and REPAIR open in GRA (91) wire between wiper motor connector C188 and wiper switch connector C221. If no open is found, REPLACE wiper motor. Wiper m otor runs. REPLACE wiper washer switch. WASHER When the Wiper Motors is in LO, Battery voltage is supplied to the motor through the WHT wire and the ground circuit is through the GRA wire, the Wiper/Washer Switch and the BLK wire to ground. Battery voltage is applied to the washer pump through the WHT wire, to the switch and to ground through the BLK wire. The washers are operational as long as the paddle switch on the Wiper Switch arm is on. WASHER MOTOR DOES NOT OPERATE TEST When the wiper is in HI, battery voltage is supplied to the motor through the WHT wire and the ground circuit 1. RESULT Place ignition switch in ACC Test lamp lights. GO to step 2. from WHT (93) wire at connector C224 to ground. Test lamp does not light. LOCATE and REPAIR open in WHT (93) wire between connector C224 and fuse block. Connect a test lamp from WHT (93) wire at washer pump connector C187 to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in WHT (93) wire between washer motor connector C187 and connector C224. 3. Connect test jum per from PNK Washer motor runs. GO to step 4. connector C187 to ground. Washer motor does not run. REPLACE washer motor. Connect test jum per from PNK (94) wire at connector C224 to ground. Washer motor runs. GO to step 5. Washer motor does not run. LOCATE and REPAIR open in PNK (94) wire between washer motor connector C187 and connector C224. Connect test jum per from PNK Washer motor runs. GO to step 6. washer switch connector C221. Washer motor does not run. LOCATE and REPAIR open in PNK (94) wire between connector C224 and windshield wiper washer switch connector C221. Washer motor runs. LOCATE and REPAIR open in BLK (150) wire between windshield wiper washer switch connector C221 and ground G200. Washer motor does not run. REPLACE windshield wiper washer switch. DIAGNOSIS -- WIPER/WASHER 2. PRELIMINARY CHECKS: Check condition of WIPER fuse. If fuse is in good condition, use the following diagnostic procedures. WIPERS DO NOT OPERATE IN ANY MODE TEST 1. Place ignition in RUN and turn wipers to HI. Connect a test lamp from WHT (93) wire at wiper motor connector C187 to ground. 2. ACTION RESULT Connect a fused jumper from BLK (150) wire at wiper switch connector C221 to ground. Test lamp does not light. LOCATE and REPAIR open in WHT (93) wire between wiper motor connector C189 and fuse block. Test lamp lights. GO to step 2. Wiper motor runs. LOCATE and REPAIR open in BLK (150) wire between wiper switch connector C221 and ground G200. Wiper motor does not run. REPLACE wiper motor. 4. 5. WIPERS DO NOT OPERATE IN HI ACTION RESULT TEST 1. Place ignition in RUN and wipers to HI. Connect a fused jumper from PPL (92) wire at wiper switch connector C221 to ground. Wiper motor does not run. LOCATE and REPAIR open in PPL (92) wire between wiper motor connector C189 and wiper switch connector C221. If no open is found, REPLACE wiper motor. Wiper motor runs. ACTION 6. Connect test jumper from BLK (150) wire at windshield wiper washer switch connector C221 to ground. Press wash switch. REPLACE wiper washer switch. WASHER MOTOR DOES NOT SHUT OFF TEST 1. Place ignition switch in RUN and wiper switch to WASH. Disconnect wiper switch connector C221. RESULT ACTION Washer motor stops pumping. REPLACE wiper washer switch. Washer motor pumps. LOCATE and REPAIR short to ground in PNK (94) wire between wiper switch connector C221 and washer motor connector C187. WINDSHIELD WIPERS/WASHERS B-37 WIPER 25 AMP 1 PROVISIONS FOR DOME LAMPS 93-3.0 WHT | PANEL DIMMER SWITCH (SEE PAGE 72) S298 (SEE PAGE 36) WIPER MOTOR 12010429 WASHER MOTOR HORN RELAY (SEE PAGE 36) WINDSHIELD WIPER/WASHER SWITCH 0 S203 | (SEE PAGE 18) l/P GROUND G200 B-38 WINDSHIELD WIPERS/WASHERS ENGINE DOES NOT CRANK AND STARTER SOLENOID DOES NOT CLICK CIRCUIT OPERATION TEST 1. START When the Ignition Switch is moved to the START position, battery is applied to the Starter Solenoid. Both solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the Starter Motor. The windings work together magnetically to pull in and hold in the Plunger. The Plunger moves the Shift Lever. This action causes the Starter Drive Assembly to rotate as it engages the Flywheel ring gear on the engine. At the same time, the Plunger also closes the solenoid switch contacts in the Starter Solenoid. Full battery voltage is applied directly to the Starter Motor and it cranks the engine. As soon as the Solenoid Switch contacts close, voltage is no longer applied through the Pull-In Winding, since battery voltage is applied to both ends of the windings. The Hold-ln Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, and Drive Assembly Solenoid Switch contacts cranking the engine. When the Ignition Switch is released from the START position, battery voltage is removed from the PPL (6) wire and the junction of the two windings. Voltage is applied from the Motor contacts through both windings to ground at the end of the Hold-ln Winding. However, the voltage applied to the Pull-In Winding is now opposing the voltage applied when the winding was first energized. The magnetic fields of the Pull-In and Hold-ln Windings now oppose one another. This action of the windings, with the help of the Return Spring, causes the Starter Drive Assembly to disengage and Solenoid Switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off. CHARGE The Generator provides voltage to operate the vehicle’s electrical system and to charge its Battery. A magnetic field is created when current flows through the Rotor. This field rotates as the Rotor is driven by the engine, creating an AC voltage in the Stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the Battery terminal. This Generator’s regulator uses digital techniques to supply the Rotor current and thereby control the output voltage. The Rotor current is proportional to the width of the electrical pulses supplied to it by the Regulator. When the Ignition Switch is placed in RUN, narrow width pulses are supplied to the Rotor, creating a weak magnetic field. When the engine is started, the Regulator sensor Generator rotation by detecting AC voltage at the Stator through an internal wire. Once the engine is running the Regulator varies the field current by controlling the pulse width. This regulates the Generator output voltage for proper battery charging and electrical system operation. The digital regulator controls the VOLTS Indicator light with a solid-state light driver. The light driver turns on the light whenever undervoltage, overvoltage or a stopped Generator is detected. 2. 3. 4. RESULT Place transmission in PARK (auto) and depress clutch pedal (man). Connect a voltmeter from PPL (6) wire at starter solenoid to ground. Turn ignition switch to START position. Battery voltage. GO to step 2. No voltage. GO to step 3 (man trans). GO to step 5 (auto trans). Connect voltmeter from PPL (6) wire to starter mounting bolts. Battery voltage. REPLACE starter solenoid. Less than battery voltage. CLEAN starter motor mounting bolts, starter motor, and mounting surface. Battery voltage. GO to step 4. No voltage. GO to step 5. Engine cranks. REPLACE clutch start switch. Engine does not crank. CHECK condition of CRNK fuse. If fuse is good, LOCATE and REPAIR open in PPL (6) wire from clutch start switch connector C219 to starter solenoid. Battery voltage. REPLACE ignition switch. No voltage. LOCATE and REPAIR open in RED (2) wires and fusible link from battery junction block to ignition switch connector C298. Disconnect clutch start switch connector C219. Connect voltmeter from YEL (5) wire at clutch start switch connector C219 to ground. Ignition switch must be in START position. Depress clutch and put transmission in neutral. Apply parking brake. Connect a fused jumper from YEL (5) to PPL (6) at clutch start switch connector C219. Turn ignition switch to START position. 5. With ignition switch OFF, connect a voltmeter from cavity B terminal at ignition switch connector C298 to ground. BATTERY IS UNDERCHARGED OR OVERCHARGED TEST 1. DIAGNOSIS - START AND CHARGE Connect voltmeter from RED (2) wire at generator connector C107. RESULT 1. Remove CRNK fuse. Connect a voltmeter to positive and negative battery terminals. Turn ignition switch to START. 2. Connect a voltmeter from negative battery terminal to engine block. 3. Connect voltmeter from positive battery terminal to starter solenoid terminal at BLK (2) wire. RESULT GO to step 2. No voltage. LOCATE and REPAIR open in RED (2) wire and fusible link from generator connector C107 to battery junction block. Reading of 13-16 volts. PERFORM Generator Bench Test. Refer to Section 6D in Service Manual. Reading of less than or greater than 13-16 volts. REPAIR generator. ACTION Voltage reading greater than 9.5 volts after 15 seconds cranking. GO to step 2. Voltage less than 9.5 volts after 15 seconds cranking. PERFORM a Battery Load Test. Refer to Section 6D in Service Manual. Less than .5 volts. GO to step 3. More than .5 volts. REPLACE negative battery cable. Less than .5 volts. REPAIR starter motor. More than .5 volts. REPLACE positive battery cable. 2. Connect generator connector C109 and terminal. Have all accessories turned off and engine running at fast idle. Connect voltmeter from battery terminal on generator to ground. ACTION Battery voltage. STARTER SOLENOID CL CKS, ENGINE DOES NOT CRANK OR CRANKS SLOWLY TEST ACTION STARTIN G/C HAR GIN G B-39 , r--------2-32.0 BLK ., , , e 6-5.0PPL _ _ _ _ _ _ _ _ _~ CLUTCH START SWITCH MTl TRANS HD, 4-SPD., WITH OVERDRIVE MT6 -_ AUTO MAN TRANS' , 5-SPD., WITH OVERDRIVE C219 6911921 1-19.0 BLK ~ ~ ~ z 0 ::;; RPOCODES + M ro ~~ ..J..J roro 0'< ai~ BATTERY !..!:, B e ..J S196 r DD- ~6-5.0PPL e I I ow IGNITION COIL (SEE PAGE 42) z ::J w tia:ixl RUN OFF o eS207 _..• ' _ _ __ LOCK 6-5.0 PPL _ _ _ _ _ _ _ _ _ __ L ACC o -~ oUi o IGNITION SWITCH 2-5.0 RED "'::J N~ 1.___________~S:9- --- 2-3.0 RED .a: o ~ '"z 5111 (SEE BATTERY JUNCTION BLOCK I /~-- ,• e = E!J lS A B C 0 ~ Z ~ F M G cD S197 • ~2-1.0RST (FUSIBLE LINK) GENERATOR Cl07 R. 'H, H = I:~ ~ 13! 1150 IL31 I m I 3 Cl00 12020163 IEiI ..J DD- I ~ ..J~ J D ...u-_l _1 _--JJ E 2 182414201440 IL 431 I 350 I I .- 2 135 1439 I 12 r L N 29 ..........- 1 __ 5 ~ CRNK ~ 10 AMP c:=::JO 2 :)-----~ 2-5.0 RED Z D- ALT 20 AMP ClOD 12020164 eD . ._ _ _ 1-19.0BLK . ._ _ _" ~ e __ 39-.6 PNK/BLK' 5206 (SEE PAGE 70) ENGINE GROUND G111 GASOLINE ENGINE 3: 6 ~~ M 9 G 6 J STARTING/CHARGING _e _ _ _ _ __ lIP o 1 UJIL419 I 3 @1: -..-:-p E D- o I 3 . ._ _ _ _ 3-5.0 PNK _ _ _ _ _ _ __ D- 1 - - 39-.6 PNK/BLK ENGINE PAGE46f :) ro 8-40 START o ~ _ _ _ _ _ _ _ _ _ __ STARl ER MOTOR 'SZ' C299 6294641 (SEE PAGE 4) . ._ _ _ 3-5.0 PNK: _ _ _ _ _ _ _ _ __ o 2-3.0RST (FUSIBLE LINK) C296 12010966 S206 -=- SHEET METAL G110 GROUND _ _ --906-.6 PPL _ _ _ _ _ _ _.~ ECM (SEE PAGE 45) , (MT60NLy) RPO CODES RPOCODES , 6-3.0 PPL e 5-3.0 VEL CLUTCH START SWITCH (MT8) C219 8911921 + + RH BATTERY _ _ .6-3.0 PPl _ _ _ LH BATTERY • 830 - SCHOOL BUS EQUIPMENT MTl - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE MT8 - MAN TRANS, 5-SPD., WITH OVERDRIVE _ _ _ _ _ _ _ _ _ _ _ _ _. . . ._ _ _ _ _ 3-5.0 PNK _ _ _ _ _. . IGNITION SWITCH ...J 3: o u -------.1:3 Cl00 12020184 liP . .- - - - - - 1-50.0 BlK 1-32.0 BlK (B3D ONLy) BATTERY JUNCTION BLOCK 5 ~~ 2Z 00 STARTER MOTOR ~ ~ • \ G (FUSIBLE LINK) ~~ • _ 2-3.0 RED S197 ~ ~ I~ S195 Iri GLOW PLUG CONTROLLER -' it oW o o M a: I M ~ '~'=~ '" 00 N ~ 39-.8 PNKlBlK • ~ _ a: L .... C GENERATOR ~j~ ALT 20 AMP '" '" I M C) = ~ fa L 12 29 ~1 r- 0-' • oe---t- ~ r----:i~~",------.416-.8 GRA _ \ , . ._ _ _ _ _ _ 417-.8 OK BLU _ _ _ _ _ _ _ _ _ _ 417-.8 OK B 417 ' - - - - t - 452 '-----" _ _ _ _ _ _• , 467-.8 LT B LU _ _ _ _ _ _ 467-.8 LT BL U cooJ TEMPERATURE SENSOR (SEE PAGE 44) (.Q;06 . .lIIIr-----·::~·.: . ~TN: ~ ~ 5 482-.8WHT ~~ '''-_-+468' IT] A - - - - 1, , ~l .- ~ D12~ CJ 11 452 !ml10 ~~ c:J 9 [IDJ [IDa ~ @ill7 ~ 439, .. - A ~ 417-.8 OK BLU _ 467-.8 LT BLU • _ _ _ _ _• • _ _ 467-.8 LT BLU • 468-.8 LT GRN _ _ _ _ _ _ , _ 468-.8LTGRN______ _ BLK -- .... -- 439-.8 PNKlBLK _ _.J ECM CONNECTOR L.. _ _ --. , S112 (SEE PAGE 52). o w a:: C> ~ J K ~ = E2J 3 L 2 M A ClOD 12020184 . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 481-1.0 RED' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _• ClOD 12020183 B-48 THROTTLE BODY INJECTION ow a:: ~ z ,, ,, ,, ,, ,, ,, ,, ,, ,, CL ~ 416-.8 GRA _ ••••••••••••• : •••• : •••• _ _ 452-.8 BLK _ _ _ _ _ _ _ , .. >.:: C> C250 12045575 r -I~' ~ ,----+481 R ll.,~ I INJECTOR 2 RN , , Ci INJECTOR 1 ~~, '- - ...__- - - - 468-.8 LT GRN co ~ - B ~ LU S101_ _ _ _ _ _ _ 452-.8 BLK t;Jr-,,_______ 452-.8 BLK _ . ClOD 12078090 - C251 12047946 412-.8 PPL _ _ _ _ _ _ _ , 12020107 (UPPER) 12020108 (LOWER) S100 • _ _ _ _ _ _ _ 416-.8 GRA ~ ___ - , + TP - , , , 412-.8PPL C124 12015791 _ r - - - -- ('-_ _ _ _ _ _ _ _ _ _ _ _ _.481-.8 RED 412 - . . . ~ . - . - . - ~.- . - . - . - . . 439-1.0 439-1.0PNKlBLK PNK/BLK I. . . . _ .-.- _ .- .- .- , ....a CIRCUIT WIRE SIZE NO. COLOR 465 1223 1222 422 .8 .8 .8 .8 DK GRN/W HT YEL/BLK LTG RN TAN/BLK 419 .8 BRN/WHT 435 420 .8 .8 GRA PPL 1226 1225 1224 1229 1228 1230 1231 437 59 .8 .8 .8 .8 .8 .8 .8 .8 .8 RED DK BLU PNK LT BLU/WHT BLK/RED DK BLU/WHT GRA/RED BRN DK GRN CAVITY DESCRIPTION CIRCUIT WIRE SIZE NO. COLOR CAVITY A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 FUEL PUMP RELAY DRIVE SOLENOID B DRIVER SOLENOID A DRIVER TCC DRIVER NOT USED NOT USED SYSTEM C H EC K LAMP NOT USED NOT USED NOT USED EVRV SOLENOID BRAKE SIGNAL 439 450 551 416 417 441 442 444 443 432 1061 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 PNK/BLK BLK/W HT TA N/W H T GRA DK BLU LT BLU/W HT LT BLU/BLK LT GRN/BLK LT G RN/W HT LTG RN O RN/BLK B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 NOT USED PRESSURE SW ITCH MANIFOLD C PRESSURE SW ITCH MANIFOLD B PRESSURE SW ITCH MANIFOLD A NOT USED NOT USED FORCE M OTOR LOW FORCE M OTOR HIGH INPUT SPEED HIGH INPUT SPEED LOW DRAC MODULE AIR CO NDITIO NING (L05) 413 412 468 467 .8 .8 .8 .8 TAN PPL DK GRN DK BLU 440 455 452 474 496 451 120 .8 .8 .8 .8 .8 .8 .8 ORN PPL BLK GRA DK BLU W HT/BLK TAN/W HT D1 D2 D3 D4 D5 D6 D7 W HT TAN/BLK BLK/RED PPL/WHT BLK/YEL YEL D8 D9 D10 D11 D12 D13 D14 D15 D16 POWERTRAIN CONTROL MODULE CO NNECTOR 423 424 453 430 1227 410 .8 .8 .8 .8 .8 .8 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 DESCRIPTION 12V IGNITION FUSED SYSTEM GRO UND SYSTEM GROUND 5V SENSOR REFERENCE TPS STEPPER CO IL A HIGH STEPPER COIL A LOW STEPPER CO IL B LOW STEPPER CO IL B HIGH MAP SERIAL DATA NO T USED OXYGEN SENSOR GRO UND OXYGEN SENSOR INJECTOR B (2) DRIVER INJECTOR A (1) DRIVER 12V BATTERY FUSED SENSOR GRO UND SENSOR GROUND 5V SENSOR REFERENCE KN O C K SIGNAL ALDL ELECTRIC FUEL PUMP FEED FUSED NO T USED NO T USED NO T USED HEI SPARK TIM ING HEI BYPASS DISTRIBUTOR REFERENCE LOW DISTRIBUTOR REFERENCE HIGH TRANSM ISSIO N TEMPERATURE COOLANT TEMPERATURE POWERTRAIN CONTROL MODULE CO NNECTO R POWERTRAIN CONTROL MODULE (PCM) PINOUTS B- 439-.8 PNK/BLK 440-.8 ORN h I 450-1,0 BLK/WHT w r 551-,8TAN/WHTr - -II- 417-.8 DK BLU -n- 416-.8 GRA :n: I 496-.S DK BLU 432-.8 LT GRN 474-.8 GRA -II- 496-.8 DK BLU ii M 455-.8 BLK 455-.S PPL 452-.8 BLK 1227-.8 BLK/YEL 410-.8 YEL I 410-.8 YEL 412-.8 PPL 1226-.8 RED 1230-.8 DK BLU/WHT I ESC KNOCK SENSOR 1225-. SDK BLU COOLANT TEMPERATURE SENSOR 1231-.8 GRA/RED 1224-.8 PNK ■■ C117 12015375 412-.8 PPL OXYGEN SENSOR INPUT SPEED SENSOR 0: 1230-.8 DK BLU/WHT ! 1231-.8 GRA/RED Jk C173 12078084 B-50 POWERTRAIN CONTROL MODULE (PCM) INPUTS - GASOLINE ENGINE W/AUTO TRANS ALTERNATOR BRACKET G101 TRANSMISSION CONNECTOR ENGINE GROUND G100 F439-.8 PNK/BLK , RPO CODES 1 I 440- 8 ORN S f l 1450-1.0 BLK/WHT W S102 (SEE PAGE 17) • w m J M f 450-.8 BLK/WHT ' I 551-.0 TAN/WHT W L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN E 4 A 450-.8 BLK/WHT ^ ^ 5 5 1 - .8 T A N /W H T - I 417-.8 DK BLU I ■ I 416-.8 GRA | 416-.8 GRA I 432-.0 LT GRN I 474-.B GRA I ■ 474-.8 G RA w m S104 (SEE PAGE 52) 417-.8 DK BLU I 416-.8 GRA ■ I 432-.8 LT GRN J I 496-.8 DK BLU I 496-.8 DK BLU 451-.8 W HT/BLK • 440-.8 ORN ’ I 455-.8 PPL I 455-.S PPL I 452-.8 BLK 452-.S BLK I12 2 7 -.8 BLK/YEL I 1227-.8 BLK/YEL I 410-.8 YEL | I 410-.8 YEL I 412-.8 PPL I 412-.8 PPL ■ 1226-.8 RED I 1226-.8 RED I 1230-.8 DK BLU/WHT 450-1.0 BLK/WHT 417-.8 DK BLU H ^ 123 0-.8D K BLU/WHT V I 1225-.8 DK BLU I m ■ 1231-.8 GRA/RED I ■ 1231 *.8 GRA/RED i 1224-.8 PNK ■ 1224-.8 p n k 413-.8 PPL 413-.8 PPL 1225-.8 DK BLU " ^ 413-.8 PPL 439-.8 PNK/BLK W rf 420 440 2 439 806 39 14Qf 120 L J 3>i f r r® 3 436 35 2 93 97 422 91 92 6 422 F 451 E 436 C B 451 I : - 450 J ALDL C100 12020183 -I A DRAC (SEE PAGE 64) C201 12020043 PROVISIONS FOR AIR CONDITIONING POWERTRAIN CONTROL MODULE (PCM) INPUTS - GASOLINE ENGINE W/AUTO TRANS B-51 439-1.0 PNK/BLK ECM-BAT 10 AMP ■ 480-1.0 ORN 450-.8 BLK/WHT I 439-1.0 PNK/BLK tW IDLE AIR CONTORL ACTUATOR IDLE AIR CONTROL ACTUATOR 0-19) (LB4/L05) EVRV i | v (L05/L19) ■ V 453-,8 BLK/RED ’ * WW 430-.8 PPL/WHT -— r j a W ^ ja m 424-.S ta n /i 430-.8 PPIVWHT M I - H B 4 3 5 -.8 G R A ^ H | B B | B B k ■ EGR (SEE PAGE 46) r * * 453-,8 BLK/RED I 1 — a 1229-.8 LT BLU/WHT ^ ■ 4 3 5 - .8 GRA 465-.8 DK GRN/WHT I— I " Tz .. z ELECTRONIC SPARK TIMING n. ■ i H 9 ■■ . M ” “ n | B ^ ^k 1^ -------------- ^"1 22 8 -8 BLK/RED * ■ 5 I I I i ^ 'H ^ | I ■ - H I i i | | n 1 ■ II M - I _ K 120-.8 TAN/WHT ■ w ^ rn I >■? ™ 422-.8 TAN/BLK V l l k M | l" ^ m M n 4 S 7 . . 8 DK BLI I' | ° ! ^ H 4 6 B -.8 D K Q R N r - H . CO w A r . J . l, . i l l ? ohm 0 5 I” 3 hm — r k ■ ■ B T 4 6 5 - . 8 D K G R N /W H T L r J ------ ------ - <422-.8 TAN/BLK ■ 467-.8 DK BLU ■ ' ■ I 468-.S DK GRN I -------------- r r ° z ( LhtfcI - r ■ |« 4 4 4 -.8 L T G R N /B L K t - INJ-2 ^ V | a | M 1 2 2 2 -.8 LT GRN g « k - -A —U “i r i t i INJ-1 H 1223-.8 YEL/BLK H | ' FUEL PUMP OIL PRESS SWITCH FUEL PUMP RELAY oioa I Jtmm ^m r C103 12052287 120-2.0 GRA 440-. 8 ORN M B-52 POWERTRAIN CONTROL MODULE (PCM) OUTPUTS - GASOLINE ENGINE W/AUTO TRANS C100 12020183 ALTERNATOR G100 BRACKET ENGINE GROUND G101 GROUND RPO CODES 1481-1.0 RED LB4 - ENGINE, 4.3L (262 CID) V6 GAS ENGINE, VIN Z L05 - ENGINE, 5.7L (350 CID) V8 GAS ENGINE, VIN K L19 - ENGINE, 7.4L (454 CID) V8 GAS ENGINE, VIN N 19-.8 BRN/WHT POWERTRAIN CONTROL MODULE (PCM) OUTPUTS - GASOLINE ENGINE W/AUTO TRANS B-53 CIRCUIT WIRE SIZE NO. COLOR 1224 1225 1226 1223 1222 451 .8 .8 .8 .8 .8 .8 PNK DK BLU RED YEL7BLK LTG R N WHT/BLK 440 .8 ORN 420 422 1234 1061 1233 1232 .8 .8 .8 .8 .8 .8 PPIVBLK TAN/BLK GRA/RED ORN/BLK DK GRN/YEL LT BLU CAVITY DESCRIPTION A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 NO T USED NOT USED PRESSURE SW ITCH MANIFOLD A PRESSURE SW ITCH MANIFOLD B PRESSURE SW ITCH MANIFOLD C SOLENOID B DRIVER SOLENOID A DRIVER ALDL NOT USED NOT USED NOT USED 12V BATTERY FUSED B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 NOT USED NOT USED NOT USED BRAKE SIGNAL TCC NOT USED NOT USED NO T USED SYSTEM C H EC K LAMP SERIAL DATA OUTPUT SPEED SENSOR LOW OUTPUT SPEED SENSOR HIGH CIRCUIT WIRE SIZE NO. COLOR 450 551 452 416 .8 .8 .8 .8 BLK/WHT TA N/W H T BLK GRA 1229 439 .8 .8 LT BLU/WHT PNK/BLK 437 1231 1230 .8 .8 .8 BRN DK BLU/W HT GRA/RED 121 476 417 .8 .8 .8 W HT BLK/PNK DK BLU 1227 433 .8 .8 BLK/YEL GRA/BLK 1229 .8 LT BLU/WHT TRANSMISSION CONTROL MODULE CONNECTOR CAVITY DESCRIPTION SYSTEM GROUND SYSTEM GROUND C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 SENSOR GROUND 5V SENSOR REFERENCE NO T USED NO T USED NO T USED NO T USED NOT USED NO T USED NO T USED NO T USED NOT USED NOT USED FORCE M OTOR HIGH 12V IGNITION FUSED D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 NOT USED DRAC MODULE INPUT SPEED LOW INPUT SPEED HIGH NO T USED ENGINE SPEED SENSOR GROUND TPS NO T USED NOT USED NO T USED NO T USED TRANSM ISSIO N TEMPERATURE MAP NO T USED FORCE MOTOR HIGH TRANSM ISSION CO NTRO L MODULE CO NNECTO R TRANSMISSION CONTROL MODULE (TCM) - PINOUTS 6.2L V8 HD DIESEL ENGINE W/HD AUTO TRANS AND OVERDRIVE B-55 Y M A / v m /v w v / ^ HOT A T A L L TIMES < ^VVWVWWWN ECM-BAT 10 AMP W VW W W W W VV yvw w vw w > S HOT IN STAR T > Za /WVWWV^ A. ECM-CRNK y 10 AMP I 250-1.0 BRN I I 250-1.0 BRN.I HOT IN STAR T OR RUN ^ >VVVVVVWV\Wv^A TRANS 1 0 AMP ^ a a r i TP SENSOR 3 f 1223-.8 YEL/BLK 250-1.0 BRN ■ ■ A M 250- 1.0 b r n | 439-.S p n k / b l k v \ 1 1440-1.0 ORN I • 476 C • 417 B Q ® jm m r 476-.S b lk /p n k ^ BLK/PNK I 417-.8 DK BLU 1416-.8 GRA I 455-.S PPL ^ 1433-.S GRA/BLK m A l416-.8GRA'*™*i^» • I S1°° i l k MAP SENSOR V " M ^ H 4 1 6 -.8 G R A H ■ H IH H -1231 INPUT SPEED SENSOR 1230-.8 DK BLU/WHT , C173 12078084 1231-.8 G R A / R E D ^ 452~ ) A 452-.S BLK I It B ENGINE SPEED SENSOR B-56 121-.8 W H T l £2 C126 12015792 121 ) TRANSMISSION CONTROL MODULE (TCM) DIESEL ENGINE W/AUTO TRANS ENGINE GROUND G100 CIRCUIT OPERATION W AIT INDICATOR DOES NOT FLASH OR FLASHES FOR THE INCORRECT AMOUNT OF TIME W HEN ENGINE IS BELOW NORMAL OPERATING TEMPERATURE The heating of the Glow Plugs is controlled by the Glow Plug Relay in the Glow Plug Controller. Battery voltage is applied to the relay contacts through the RED wire from Junction Block. The relay is operated by a Solid-State Controller. The Controller responds to engine temperature and also to an Ignition Switch Start Input. When the Ignition Switch is turned to RUN, battery voltage is applied to the Enable Input of the Controller. The Glow Plug Relay within the Controller will be energized for approximately five seconds during which it applies voltage to the Glow Plugs and WAIT Indicator. After the initial time period the relay will be de-energized for five seconds then will cycle ON/OFF for approximately 10 seconds. When the Glow Plug Controller receives the Start Input, the Glow Plugs and WAIT Indicator will cycle ON/OFF after the Ignition Switch is returned to RUN. After approximately 25 seconds the Controller will open the Glow Plug Relay and the heating of the plugs stops. DIAGNOSIS - GLOW PLUGS TEST RESULT 1. Place ignition switch in RUN position. Connect test lamp from RED (2) wire at glow plug controller connector C190 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire and fusible link from glow plug controller connector C190 to battery junction block. 2. Connect test lamp from PNK (3) wire at glow plug controller connector C128 to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in PNK (3) wire from glow plug controller connector C128 to ground terminal G102. Connect test lamp from PNK (3) wire to BLK (150) wire at glow plug controller connector C128. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from glow plug controller connector C128 to ground terminal G102. Connect test lamp from PPL (906) wire at glow plug controller connector C128 to ground. Move ignition switch to START position. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in PPL (906) wire from glow plug controller connector C128 to starter motor. Test lamp lights. REPLACE glow plug controller. Test lamp does not light. GO to step 6. Disconnect glow plug controller connector C128. Using a positive polarity ohmmeter, check continutity between ORN (503) and BLK (150) wires. Reading of 2 ohms or less. GO to step 7. Reading greater than 2 ohms. LOCATE and REPAIR open in ORN (503) wires from glow plug controller connector C128 to splice S116. Reconnect glow plug controller connector. Connect test lamp from ORN (503) and ORN/BLK (509) wires at glow plug controller connector C191 to ground. Turn ignition switch momentarily to START and then release to RUN position. Test lamp cycles on and off for approximately 25 seconds then goes off. GO to step 8. Test lamp does not light or cycles for the incorrect time. REPLACE glow plug controller. Test lamp lights for all glow plugs. LOCATE and REPAIR open in ORN (503) and ORN/BLK (509) wires from glow plug to glow plug controller connector C191. Test lamp does not light for one or more glow plugs. REPLACE glow plug(s) where test lamp did not light. 3. PRELIMINARY CHECKS: A check of the glow plug system should be performed before doing diagnostic procedures. With engine below normal operating temperature, turn ignition switch to RUN. The WAIT indicator should light. After approximately 10 seconds, the WAIT indicator must begin to flash for an additional 10 seconds and then go out. Turn ignition switch to OFF and then momentarily to START and return to RUN position. The WAIT indicator should flash for approximately 25 seconds and then go out. ACTION 4. With engine at normal operating temperature, turn ignition switch to RUN. The WAIT indicator should flash. 5. 6. 7. 8. Place ignition switch to OFF position. Connect test lamp from ORN (503) and ORN/BLK (509) wires at glow plug controller connector C191 to ground. Remove all connectors from glow plugs. Connect one lead of test lamp to battery voltage and other lead to each glow plug. GLOW PLUGS B-59 I 1-32.0 BLK RIGHT BANK GLOW PLUGS a: eg O 0) ci p o 1 LEFT BANK GLOW PLUGS GROUND G113 B-60 SHEET METAL GROUND G111 GLOW PLUGS I RIGHT BANK GLOW PLUGS GROUND G114 LEFT BANK GLOW PLUGS 6-5.0 PPL I 2-3.0 RED I 505-.5 RST I (FUSIBLE LINK) 6-5.0 P P L ! RPO CODES B3D - SCHOOL BUS EQUIPMENT MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE MT8 - MAN TRANS, 5-SPD., WITH OVERDRIVE 2-8.0 RED *z CL C190 CLUTCH START SW (MTS ONLY) (SEE PAGE 41) GLOW PLUG CONTROLLER I 509-5.0 ORN/BLK S114 (SEE PAGES 19, 20) I 503-5.0 ORN 503-1.0 ORN C299 12010966 l/P S205 ENGINE 3 CD 0 1 3-3.0 PNK I 508 : 503 450 3 68 J 2 < 430 2 : 24 6 r 35 , i 94 508 7 15 593 9 14 29 821 93 5 11 12 : C100 12020184 1505-1.0 YEL1 ENGINE GROUND G102 6-5.0 PPL 2-5.0 RED GLOW PLUGS B-61 WATER IN FUEL INDICATOR LIGHTS WITH NO WATER IN FUEL CIRCUIT OPERATION TEST therm ostatic switch. The switch opens or closes, to turn the heater off or on, depending on the temperature of the fuel. The Diesel Fuel Filter System combines six functions into a single package: 1. It heats diesel fuel to prevent wax-plugging of the filter; 2. It combines very small droplets of water in the fuel into larger drops and separates the water from the fuel; 3. It filters the diesel fuel; 4. It detects an excessive pressure drop indicating filter plugging; (Vacuum Switch) 5. It detects the presence of excess water in the fuel; and 6. It provides a means to drain the water it has separated. The Solid-State Water In Fuel Sensor applies voltage to a Probe. When the Probe touches water, the Module closes a switch. This completes a circuit to ground to light the SERVICE FUEL FILTER Indicator. A times delay circuit in the Water In Fuel Module grounds the Indicator bulb briefly to test the bulb each time the system is turned on. DIAGNOSIS - DIESEL ENGINE FUEL CONTROLS FUEL HEATER DOES NOT O P E R A TE _____________ 2. ACTION RESULT Disconnect fuel heater connector C132. Place ignition switch to RUN position. Connect voltmeter from PNK/BLK (39) wire at fuel heater connector C132 to ground. Battery voltage. GO to step 2. No voltage. CHECK condition of ALT fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) from fuel heater connector C132 to fuse block. Connect voltmeter from PNK/BLK (39) wire to BLK (150) wire at fuel heater connector C132. Battery voltage. REPLACE fuel heater. No voltage. LOCATE and REPAIR open in BLK (150) wire from fuel heater connector to ground G102. B-62 FUEL CONTROLS DIESEL ENGINE ACTION Water in fuel indicator stays on. LOCATE and REPAIR open in YEL/BLK (508) wire between water in fuel sensor connector C130 and water in fuel indicator. Water in fuel indicator goes out. REPLACE water in fuel sensor. WATER IN FUEL INDICATOR DOES NOT LIGHT BRIEFLY WITH ____________ IGNITION SWITCH TURNED TO RUN TEST RESULT ACTION 1. Disconnect water in fuel sensor connector C130 and place ignition switch in RUN. Connect a voltmeter from PNK/BLK (39) wire at water in fuel sensor connector C 130 to ground. Battery voltage. GO to step 2. No voltage. CHECK condition of ALT fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire from water in fuel sensor connector C130 to fuse block. 2. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in BLK (150) wire from water in fuel sensor connector C 130 to ground G102. Battery voltage. REPLACE water in fuel sensor. No voltage. CHECK water in fuel lamp. If lamp is good, LOCATE and REPAIR open in YEL/BLK (508) wire between water in fuel sensor connector C130 and water in fuel indicator. The Fuel Heater is operated by a built-in thermostatic switch. When the switch is closed, battery voltage is applied to the heater from the ALT Fuse. An electric fuel pum p delivers diesel fuel from the tank to the fuel filter. As fuel enters the filter, it passes first through the Fuel Heater. The heater contains a 1. Place ignition switch in RUN position. Disconnect water in fuel sensor connector C130. The fuel then passes through the Primary and Secondary filters. Next the fuel flows through the water coalescer. Here the droplets of water in the fuel are combined into larger drops, the drops fall to the water reservoir in the filter. When fuel flows from the Fuel Filter Assembly to the injection pump, it is clean and free of water. The Fuel Filter Assembly consists of the following main parts: Fuel Heater, the Water In Fuel Sensor, the Fuel Pressure Switch, and a Filter. The Filter contains the "coalescer" (the device that combines small droplets of water into larger ones) and the filter/separator. TEST 1. RESULT 3. Connect voltmeter from PNK/BLK (39) to BLK (150) wire at water in fuel sensor connector C130. Connect voltmeter from YEL/BLK (508) wire at water in fuel sensor connect or C130 to ground. ALT 20 AMP I 39-. 8 PNK/BLK FAST IDLE SOLENOID C135 12004267 39-.8 PNK/BLK GENERATOR (SEE PAGE 41) WATER IN FUEL SENSOR FUEL HEATER 508-.8 YEL WATER IN FUEL LAMP (SEE PAGE 70; I ---------------- I FUEL SHUT OFF VALVE ENGINE GROUND G102 S208 (SEE PAGE 70) 3 9 ,8 PNK/BLK * l/P CLUSTER (SEE PAGE 69) FUEL CONTROLS DIESEL ENGINE RPO CODES M Tt - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE MT8 - MAN TRANS, 5-SPD., WITH OVERDRIVE ECM-CRNK 10 AMP $ I 439-1.0 PNK/BLK I o S203 CO DRAC D _i O _/ < z o B 1 HiHl 11226 2 11223! Ii23a ' 3 1224) 4 14 2 2 1 IZZI 5 o Ui 1 p uu □ y o X > O X ?! § g (SEE PAGE 18) 1222' ECM/PCM CONNECTOR 5 6 C251 12052175 n rrm (l2 2 £ 8 □ fisa 9 CZ3 1123-f 10 C=J < 4 3 7 ] 11 L«bJ CZI 12 [4 2 0 ] 11229 x tU > A 7 GT100 437-.8 BRN 12020107 (UPPER) 12020108 (LOWER) 1233-.8 DK GRN/YEL vss ENGINE 150-.8 BLK (MT8) I 439-.S PNK/BLK 4 1232-.8 LT BLU 824-.8 LT BLU/BLK W/YEL ■ 1233-.8 DK GRN/YEL 1232-.8 LT BLU OUTPUT SPEED SENSOR (MT1) 64 " i mS j: B i ! T « a r 1233-.8 DK GRN/YEL I ____________ i 12020183 ■ 1232-.8 LT B L U ^ ^ ^ M M B M DIGITAL RATIO ADAPTER CONTROLLER (DRAC) GASOLINE ENGINES W/MAN OR AUTO TRANS AND DIESEL ENGINES W/AUTO TRANS l/P GROUND G200 ALT 20 AMP 39-.8 PNK/BLK 39-.S PNK/BLK I I \ \ I f _\_L ll M: t I! 30 24 18 19 : 68 3. 1233 T 505 ), r DRAC 11 VEHICLE SPEED SIGNAL CLUSTER 9 15 14 S24-.8 LT BLU/BLK 12 29 1232 VEHICLE SPEED INPUT 1232-.8 LT BLU CC I _______ C100 12020184 39>.8 PNK/BLK V 150-.8 BLK 39 12 VOLT (IGNITION) 150 GROUND 1233 VEHICLE SPEED SIGNAL INPUT ♦ SPEEDOMETER (SEE PAGE 71) C292 12066130 1233-.8 DK GRN/YEL I r S203 (SEE PAGE 19) VSS 1233-.8 DK GRN/YEL 1232-.8 LT BLU ■ ■ ■ *•1232 C185 12020600 3 GE3 C100 12020183 l/P GROUND G200 DIGITAL RATIO ADAPTER CONTROLLER (DRAC) DIESEL ENGINE W/MAN TRANS B-65 DIAGNOSIS - INSTRUMENT PANEL: GAGES AND INDICATORS CIRCUIT OPERATION TEMPERATURE GAGE PRELIMINARY CHECKS: Check condition of GAUGES and INST LPS fuses. If fuses are in good condition use the following diagnostic procedures. Battery voltage is applied to the Park Brake Warning Lamp when the Ignition Switch is in RUN or START. The Park Brake Switch provides a ground when the Park Brake is applied. The Park Brake Warning Lamp illuminates to alert the driver. The Temperature Gage is also operated by two coils. Battery voltage is applied to both coils. One is grounded directly and the other is grounded through the Temperature Sender. This has 55 ohms resistance at 127°c (260°F) (hot coolant) and its resistance becomes greater at lower temperatures. It is approximately 1400 ohms at 38°C (100°F). This causes the current through the Sender and one coil to increase as the coolant temperature increases. This m oves the pointer. SERVICE BRAKES WARNING LAMP LOW COOLANT INDICATOR (DIESEL) Battery voltage is applied to the Service Brakes Warning Lamp when the Ignition Switch is in RUN or START. The Brake Pressure Switch closes to provide a ground and illuminate the lamp when there is a loss of brake fluid pressure in one of the two brake systems. This could be caused by a leak in one of the brake lines. The Low Coolant Indicator comes on to warn the driver when a low level of coolant exists in the radiator. Battery voltage is applied to the Low Coolant Module. When a low coolant condition exists, a signal is sent to the Low Coolant Module from the Low Coolant Sensor. The Low Coolant Module will provide a ground to the Low Coolant Indicator. The operation of an individual Indicator is described along with its circuit. Refer to the schematic and text for the circuit that is indicated below each of the Indicators. PARK BRAKE WARNING LAMP FUEL GAGE The pointer of the Fuel Gage is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the E-coil and the circuit divides at the opposite end of the coil. One path continues to ground through the F-coil. Another goes to ground through the variable resistor of the Fuel Gage Sender. When the tank is low, the resistance of the Sender is low. A large flow of current passes through the E-coil and the Fuel Gage Sender resistor. This moves the pointer toward E on the scale. When the tank is full, the Sender resistance is high. More current now flows through the F-coil, moving the pointer toward F on the scale. With two coils operating the pointer, the Gage is not affected by changes in the system’s battery voltage. The Low Coolant Sensor is not a switch that opens and closes. It has a very high resistance to ground, more than 50,000 ohms, when the engine coolant level is low. This causes the Low Coolant Module to light the Low Coolant Indicator. With more of the Sensor covered by coolant, its resistance decreases. When the fluid level is good, the resistance will be less than 10,000 ohms. With the Sensor resistance between 10,000 and 50,000 ohms, the Sensor is partly covered and the fluid is not low enough to cause the warning to be displayed. FUEL GAGE INDICATES FULL OR BEYOND AT ALL TIMES TEST 1. 2. The engine oil pressure is displayed by the Oil Pressure Gage. The pointer of the Gage is moved by two coils, and its operation is similar to that of the Fuel Gage. TEST 1. B-66 INSTRUMENT PANEL Fuel gage indicates full. LOCATE and REPAIR open in PNK (30) wire between fuel pump connector C400 and fuel gage. If no open is found, REPLACE fuel gage- Fuel gage indicates empty. GO to step 2. Fuel gage indicates full. LOCATE and REPAIR open in BLK (150) wire between fuel pump connector C400 and ground G400. If no open is found, REPLACE fuel pump. Fuel gage indicates empty. REPAIR/REPLACE fuel pump. Disconnect fuel pump and place ignition switch to RUN. RESULT Refer to Light Duty Truck Fuel, Driveability and Emissions Service Manual, Section 3. REPAIR/REPLACE fuel pump. Fuel gage indicates empty. LOCATE and REPAIR an open in PNK (30) wire between fuel pump connector C400 and fuel gage. If no open is found, REPLACE fuel gage. FUEL GAUGE IS INACCURATE TEST WATER IN FUEL WARNING INDICATOR Refer to Fuel Controls (Diesel), Page 62 1. Refer to Glow Plugs (Diesel), Page 59 RH/LH TURN SIGNAL INDICATORS Refer to Front Exterior Lamps, Page 33 Refer to Headlamps, Page 22 Disconnect fuel pump connector C400. Connect one RED lead of J 34029-A Multimeter to PNK (30) wire and other to ground. Set resistance dials to 0 ohms and then to 90 ohms. Fuel gage should indicate empty and then full. (Allow time for gage to reach full due to anti-slosh device.) RESULT ACTION Gage responds correctly. CHECK BLK (150) wire for high resistance. If wire is good, REPAIR/REPLACE fuel pump. Gage does not respond correctly. CHECK for high resistance in PNK (30) wire. If wire is good, REPLACE fuel gage. TEMPERATURE INDICATOR STAYS ON AT ALL TIMES WITH IGNITION SWITCH IN RUN TEST RESULT ACTION DRL INDICATOR Refer to Headlamps with Canadian Daytime Running Lamps, Page 25 ACTION Fuel gage indicates full. CHECK ENGINE (GASOLINE) INDICATOR HIGH BEAM INDICATOR The Oil Pressure Sender is connected to the junction of the two coils. It has low resistance when the oil pressure is low, and 90 ohms resistance when the oil pressure is high. This changing resistance changes the current flow through coils. The magnetic fields of the coils move the pointer from low to high. Connect fused jumper form PNK (30) wire to BLK (150) wire at fuel pump connector C400. ACTION FUEL GAGE INDICATES EMPTY WHEN THERE IS FUEL IN THE TANK GLOW PLUG INDICATOR OIL PRESSURE GAGE Disconnect fuel pump connector C400 and place ignition switch to RUN. Connect a fused jumper from PNK (30) wire at fuel pump connector C400 to ground. RESULT 1. Disconnect temperature sender connector C108 (Gasoline) or C106 (Diesel) and place ignition switch to RUN. Observe temperature indicator. Indicator stays on. LOCATE and REPAIR short in DK GRN (35) wire. If wire is good, REPLACE instrument cluster. Indicator goes off. REPLACE temperature sender. OIL PRESSURE GAGE INDICATES HIGH PRESSURE AT ALL TIMES TEMPERATURE GAGE INDICATES COLD ALL THE TIME TEST RESULT 1. Disconnect temperature sender connector C108 (Gasoline) or C106 (Diesel). Ground the OK GRN (35) wire at temperature sender connector C108 (Gasoline) or C106 (Diesel). ACTION Temperature gage indicates hot. REPAIR/REPLACE temperature sender. Temperature gage does not indicate hot. lOCATE and REPAIR open in DK GRN (35) wire between temperature sender connector C108 (Gasoline) or C106 (Diesel) and temperature gage. If wire is good, REPLACE temperature gage. TEMPERATURE GAGE IS NOT ACCURATE TEST RESULT 1. Disconnect temperature sender connector C108 (Gasoline) or C106 (Diesel). Connect RED lead from J 34029-A Multimeter to DK GRN (35) wire and other lead to ground. Adjust resistance dials to 1400 ohms and then to 55 ohms. Temperature gage should indicate cold then hot. ACTION Gage indicate correctly. REPLACE temperature sender. Gage is not correct. lOCATE and REPAIR open in DK GRN (35) wire between temperature sender connector C108 (Gasoline) or C1 06 (Diesel) and temperature gage. If wire is good, REPLACE temperature gage. TEMPERATURE GAGE INDICATES HOT WITH ENGINE COOLANT BELOW OPERATING TEMPERATURE AND IGNITION SWITCH IN RUN TEST RESULT 1. Disconnect temperature sender connector C108 (Gasoline) or C106 (Diesel) and place ignition switch to RUN. ACTION Temperature gage indicates cold. REPLACE temperature sender. Temperature gage does not indicate cold. lOCATE and REPAIR an open in OK GRN (35) wire between temperature sender connector C108 (Gasoline) and 106 (Diesel) and temperature gage. If no open is found, PERFORM diagnostic procedures under symptom "Temperature Gage Is Not Accurate. TEST Disconnect oil pressure sender connector C118 and place ignition switch to RUN. Connect a fused jumper from TAN (31) wire at oil pressure sender connector C118 to ground. RESULT Oil pressure gage indicates low pressure or indicator lights. 1. Disconnect oil pressure sender connector C118. Connect one RED lead of J 34029-A Multimeter to TAN (31) wire at oil pressure sender connector C118 and other lead to ground. Set resistance dials to 0 ohms and then to 90 ohms. The oil pressure gage should indicate low pressure and then high pressure. RESULT ACTION Oil pressure gage indicates correctly. REPLACE oil pressure sender. Oil pressure gage does not indicate correctly. lOCATE and REPAIR open in TAN (31) wire between oil pressure sender connector C118 and oil pressure gage. If wire is good, REPLACE oil pressure gage. REPLACE oil pressure sender. Oil pressure gage indicates high pressure or indicator does not light. lOCATE and REPAIR open in TAN (31) wire and bUlb. If wire and bulb are good, REPLACE oil pressure gage. OIL PRESSURE GAGE INDICATES LOW PRESSURE WHEN OIL PRESSURE IS GOOD RESULT TEST 1. Disconnect oil pressure sender connector C118 and place ignition switch to RUN. ACTION Oil pressure gage indicates high pressure or indicator light goes out. REPLACE oil pressure sender. Oil pressure gage indicates no or low pressure or indicator light stays on. lOCATE and REPAIR open in TAN (31) wire between oil pressure sender connector C118 and oil pressure gage. If wire is good, REPLACE oil pressure gage. LOW COOLANT INDICATOR DOES NOT LIGHT WITH COOLANT LEVEL LOW (DIESEL ONLy) RESULT TEST ACTION 1. Disconnect low coolant warning switch connector C150 and place ignition switch to RUN. Observe low coolant indicator light. low coolant indicator lights. REPLACE low coolant warning switch. Low coolant indicator does not light. GO to step 2. 2. Disconnect low coolant warning module connector C236. Connect voltmeter from PNK/BLK (39) wire at low coolant warning module connector C236 to ground. Battery voltage. GO to step 3. No voltage. lOCATE and REPAIR open in BlK/ORN (550) wire. If no open is found, CHECK condition of GAUGES fuse. 3. Connect voltmeter from BlK/ORN (550) wire to BlK (150) wire at low coolant warning module connector C236. Battery voltage. GO to step 4. No voltage. lOCATE and REPAIR open in BlK (150) wire between low coolant warning module connector C236 and ground G200. 4. Connect voltmeter from GRA (69) wire at low coolant warning module connector C236 to ground. Battery Voltage. GO to step 5. No voltage. lOCATE and REPAIR open or short to ground in GRA (69) wire from low coolant warning module connector C236 to low coolant warning lamp. 5. Connect voltmeter from BlK/ORN (550) wire to YEL/BlK (68) at low coolant warning module connector C236. Battery Voltage. LOCATE and REPAIR open in VEL/BlK (68) wire from low coolant warning module connector C236 to low coolant warning switch connector C1 50. No voltage. REPLACE low coolant warning module. OIL PRESSURE GAGE IS NOT ACCURATE TEST ACTION INSTRUMENT PANEL 8-67 / LOW COOLANT INDICATOR IS LIT WHEN COOLANT LEVEL IS GOOD TEST Connect a fused jumper from low coolant warning switch connector C150 to ground. Place ignition switch to RUN and observe low coolant indicator light. 8-68 INSTRUMENT PANEL RESULT ACTION Low coolant indicator goes out. REPLACE low coolant probe. Low coolant indicator stays lit. LOCATE and REPAIR open in YELlBLK (68) wire. If wire is good, follow diagnostic procedures listed under symptom "Low Coolant Indicator Does Not Light With Coolant Level Low." I I I I I I I I I I I I I I I I I I I ILLUM ILLUM ILLUM ILLUM ILLUM ILIUM ILLUM 8 -150 : r------f---, ,CANADIAN ~:; HIGH BEAM LEFT TURN (.... f-- RIGHT 14 TURN ~ 11 ® I ~~~II~~Er-~v~ 50 : ,LAMP 150 1,5 I 593: , I : 'I L _ _ _ _ _ _ _ _ .J SERVICE TRANSMISSION (629W/DRL) G--:[)- 1234 r- - 508 'f-""'" WATER IN FUEL (DIESEL ONLy) 39 39 39 t-- f-- 419 68 -'- LOW COOLANT '-~ SERVICE ENGINE SOON SERVICE BRAKE PARK BRAKE GLOW PLUG (DIESEL ONLY) SPEEDOMETER VOLT /, ..--~------------~~----------------~---------------t----------~--+-t1~ .~ c:::: "'" g •p = .", ~. · .~ _30 --_IHtt_IIfft.. .= 824 - ......__;t+t-.:iS .... 39 --...t-i=:::::ttt-e", '" - F== F== .M .."'. ~ .. F= I ~ ~ TEMP C205 12040746 508 - 68-----~ : § “ TURN SIGNAL SWITCH / \ 8-.5 GRA I 44 LIGHT SWITCH A B C d E F 39 * 30 ,s . 150- DOME I OFF • 156 l/P CLUSTER CONNECTOR (SEE PAGE 69) CIRCUIT BREAKER' 25 AMP / ----/ I 150 824 419 39 33 11,1 |1 5 0 -.8 B L K | f— _ 35 HEAD 40- 150 'PARK 31 OFF 1S0 ' PARK 15 I': HEAD 14 .150 11 S203 (SEEPAG E 18) LIGHT' SWITCH ■ 150-3.0 BLK I l/P GROUND G200 B-72 INSTRUMENT PANEL LAMPS ALARM W ILL NOT SOUND CIRCUIT OPERATION TEST Vehicles equipped with the Hydro-Boost Brake system have an optional warning harness that plugs into the l/P harness. Refer to Section 5A1 of the 1991 R/V, P Light Truck Service Manual for further description and operation of the Hydro-Boost System. 1. DIAGNOSIS - BRAKE WARNING SYSTEM 2. PRELIMINARY CHECKS: 1. 2. 3. 3. Check condition of GAUGES fuse. Replace if needed. Place Ignition Switch in RUN. For vehicles equipped with Hydro-Boost Brake system, verify hydraulics as described in Section 5A1 of the 1991 R/V, P Light Truck Service Manual. If alarm continues to malfunction, use the following procedures. BRAKE INDICATOR REMAINS ON WITH IGNITION SWITCH IN RUN AND PARK BRAKE OFF TEST 1. 2. Disconnect park brake switch connector C204. Disconnect brake pressure warning switch connector C105. RESULT ACTION Brake indicator lamp does not go out. GO to step 2. Brake indicator lamp goes out. CHECK adjustment of park brake switch. If adjustment cannot be corrected, REPLACE park brake switch. Brake indicator lamp does not go out. LOCATE and REPAIR short to ground in BLK (111) wire between brake pressure switch connector C105 and indicator lamp. Brake indicator lamp goes out. 4. RESULT ACTION Connect a test lamp from PNK/BLK (39) wire at alarm connector C217 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in PNK/BLK (39) wire between alarm connector C217 and fuse block. Connect test jum per from BLK Alarm sounds. GO to step 3. C217 to ground. Alarm does not sound. REPLACE alarm. Connect test jum per from BLK (11) wire at delay module connector C116 to ground. Alarm sounds. GO to step 4. Alarm does not sound. LOCATE and REPAIR open in BLK (11) wire between alarm connector C217 and delay module connector C216. Connect test jum per from TAN (966) wire at hydro-boost pressure switch connector C148 to ground. Alarm sounds. REFER to Section 5A1 of the 1991 R/V, P Light Truck Service Manual. Alarm does not sound. LOCATE and REPAIR open in TAN (966) wire between hydro-boost pressure switch connector C148 and delay module connector C216. If no open is found, REPLACE delay module. ALARM WILL NOT SHUT OFF TEST 1. CHECK for a possible leak or loss of brake fluid. 2. 3. Disconnect brake pressure warning switch connector C105. Disconnect delay module connector C216. Disconnect hydro-boost pressure switch connector C148. Connect a test lamp from TAN (996) wire at hydro-boost pressure switch connector C148 to positive battery terminal. RESULT ACTION Alarm stops. GO to step 2. Alarm continues to sound. CHECK for possible leak or loss of fluid in the brake system. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR short to ground in BLK (11) wire between delay module connector C216 and alarm connector C217. Alarm continues to sound. LOCATE and REPAIR short to ground in TAN (996) wire between hydro-boost pressure switch connector C148 and delay module connector C216. If no short is found, REFER to Section 5A1 of the 1991 R/V, P Light Truck Service Manual. Alarm stops. REPLACE delay module. BRAKE WARNING SYSTEM SCHOOL BUS B-73 C218 12004888 ~BA~ _ _ _ 39-.8PNK/BLK_ - - - - - - - - - - - - - - - - - I L I [iJpUJ lEI 0 S ~ 1.5 OHM RESISTOR L [iJ~ill lID lID 00 rID lID [ru 0 ill ACC GAUGES u0 ALARM GAUGES 20 AMP Ou . ._ _ _ _ _ _ _ _ _ 966-.8 TAN _ _ _ _ _ _ _ _ _.. ~ TRANS ECM-BAT HTR ACC-RADIO (SEE (SEE PAGE PAGE 69) € C217 8905825 PWR ~[AJ~~ HORN/OM INSTR-LPS liP l/P CLUSTER CONNECTOR lEI 0 ~DO~OO TAIL LPS INJ ~OODD[)£] ~P-HAZ E~r [jUXO WIPER Jib Pu::g FUSE BLOCK FRONT REAR HYDRO IOGST SWITCH HI AlARM 111 ...J ~ 12089776 o C216 8900655 FLASHER UNIT o ::s Q D A S402 yf ia i 9-.8 BRN w a rn • 19 c4oo |kg) RH LICENSE LAMP ) I9 -.8 BRN I I • S400 2977107 ■ 24-.8 LT G RNa NOTE: This harness is shipped along with the vehicle and is installed by the body builder. 12034342 9-.S BRN < S401 C150 § h - .8 BLK-= ® LH LICENSE LAMP M I 1 5 0 - .8 BLK | S404 .8 BLK* I 18-.8 YEL« M b it * .8 b l k - © LH BACKUP LAMP C403 2984855 LH TAIL, STOP AND TURN LAMP ^ B C405 2977107 PROVISIONS FOR LH SIDE MARKER 24-.8 LT GRN B-76 REAR LAMP HARNESS ^ - S BLK ^ RPO CODES TRANSMISSION BACKUP LAMP SWITCH (AUTO TRANS ONLY) MT1 - AUTO TRANS, HD, 4-SPD., WITH OVERDRIVE MT8 - MAN TRANS, 5-SPD., WITH OVERDRIVE C214 2973407 REAR JD)H l a m p 24-1.0 LT GRN HARNESS BACKUP LAMP SWITCH (4 SPEED MAN TRANS ONLY) > 1 1C 1 O C100 12020183 BACKUP LAMPS B-77 y^AVW V'W W Vf S HOT AT ALL TIMES < i^VWVVVWVV^T LIGHT SWITCH TAIL LPS 20 AMP 44 140-1.0 ORN 150- PANEL DIMMER SWITCH ,x ■ 156 DOME LIGHT SWITCH I l S l r i 11 so 11 se I 4 4 lC ^ 2 - CIRCUIT BREAKER 25 AMP .PARK I HEAD OFF r -. * PARK HEAD REAR BODY CONNECTOR ■ 9-2.0 BRNI jj 12065158 340 : 450 120 39 3 419 2 31 439 35 2 440 6 94 906 33 J I 30 24 J I9 18 19 K [C ) n 93 434 , r 11 L 12 M 15 593 14 29 9 N P o o B-78 TAILLAMPS, REAR MARKER AND LICENSE LAMPS REAR LAMP HARNESS C402 CIRCUIT OPERATION EGR VALVE VACUUM SYSTEM VACUUM SYSTEMS A vacuum-operated component uses the force of normal air pressure working against the lower air pressure of a partial vacuum to operate the component. The vacuum created within the inlet manifold when the engine is running is stored in a vacuum tank in the engine compartment. A check valve in the line feeding vacuum to the tank keeps the stored vacuum from weakening when inlet manifold vacuum drops during high speed or high power operation. Vacuum is routed through hoses (and in some cases, tubing) to a mechanical or electric valve that provides a means of controlling the vacuum-operated component. When the valve is open, it allows vacuum to go to an actuator that actually operates the component. When the component is to be returned to its original position, the valve cuts off the vacuum to the actuator hose and vents the hose to normal air pressure. A typical actuator is a metal shell with a movable shaft that retracts and extends to mechanically operate the component. A flexible diaphragm separates the interior of the shell into two chambers - a sealed chamber to which vacuum can be admitted, and an open chamber exposed to normal air pressure. The movable shaft is attached to the center of the diaphragm and extends from the open chamber. When the vacuum is directed to the sealed chamber, normal air pressure presses on the other side of the diaphragm and causes it to retract the shaft. When the vacuum is cut off, the sealed chamber is vented to outside air to balance the air pressure on both sides of the diaphragm and eliminate the force that retracted the shaft. A coiled spring within the sealed chamber expands to push the diaphragm back to its original positions. This extends the shaft. EXHAUST GAS RECIRCULATION VACUUM SYSTEM All 1991 P-Truck gasoline engines are equipped with an exhaust gas recirculation (EGR) system. The EGR system allows a small amount of exhaust gas to flow from the exhaust manifold into the inlet manifold when the throttle is opened beyond idle and inlet manifold vacuum is normal. This reduces combustion temperatures in the engine to control oxides of nitrogen emissions. The EGR valve is operated by an integral vacuum actuator that controls a pintle within the valve. The pintle remains closed to prevent exhaust gas recirculation until vacuum is applied to the actuator. The vacuum causes the pintle to open, allowing a measured flow of exhaust gas to enter the inlet manifold. The EGR system remains closed during periods of engine idle and deceleration to prevent rough idle from excessive dilution of the fuel-air mixture. It also remains closed at wide-open throttle to prevent voltage loss. At other times, it rapidly cycles open and closed to modulate the flow of exhaust gas as required. Under certain circumstances, it may remain fully open to provide the maximum EGR. A manifold absolute pressure (MAP) sensor measures the strength of the vacuum in the EGR vacuum circuit and sends a signal back to the electronic control module (ECM). If actual vacuum differs from the preferred vacuum as calculated by the ECM, the ECM will adjust the on-off intervals of the EGR valve to correct the flow of exhaust gas into the cylinders. This provides the required control of oxides of nitrogen emissions while retaining engine performance under all operating conditions. The ECM also uses the signal from the MAP sensor to control fuel delivery and ignition timing. Vacuum for the EGR system is taken from the throttle body and routed through a hose to the electronic vacuum regulator valve (EVRV) solenoid (V8 engine) or to the EGR valve solenoid (V6 engine). The solenoid is controlled by the 435 circuit from the ECM. When the solenoid opens the electronic vacuum regulator valve or the EGR valve, vacuum reaches the EGR actuator through another vacuum hose and opens the EGR pintle valve to allow exhaust gas to flow into the inlet manifold. When the EVRV solenoid or the EGR valve solenoid is released, the valve vents the EGR actuator to outside air to close the EGR pintle valve. A leak in the EGR (exhaust gas recirculation) vacuum system can upset the ECM’s programmed control of exhaust gas recirculation and adversely affect engine operation. Too much exhaust gas recirculation at idle or cruise can result in the engine stalling after closed throttle deceleration, surging during steady throttle cruising, or a rough idle. Too little exhaust gas flow allows combustion temperatures to become too high and bring about detonation ("spark knock") or an overheated engine. In addition, nitrous oxide emissions may be high enough to cause the vehicle to fail an emissions test. Because the source of an EGR system symptom might be traced to a mechanical or electrical condition as well as a faulty vacuum system, an effective systematic diagnosis procedure should examine all three categories of components - not just the vacuum system alone. Therefore, no exclusive vacuum system diagnosis procedures are provided here. For more information on the EGR system, refer to the 1991 "Fuel and Emissions Service Manual." DIAGNOSIS Condition most likely to cause vacuum system problems include hoses that leak or become disconnected. With the engine running, either condition is easily detected from the hiss of air at the opening. Other common vacuum problems are kinked or obstructed hoses, hoses connected incorrectly or binding components. A vacuum pum p can be used as a vacuum source to operate com ponents and test the system. The built-in vacuum gage of the pump provides a means of checking for a vacuum leak as well. Once vacuum is applied to operate the component, the gage should hold steady until the vacuum is purposely released. On vacuum systems that are controlled by electrical or electronic switches, check for a blown fuse, wiring that is cracked, frayed or burned, and high resistance in connectors of the control circuit(s) before checking for a suspected vacuum system problem. S102 (SEE PAGES 42, 52) I 45O-.0 BLK/W HT ■ • S 111 (SEE PAGE 46) P39-.8 PNK/BLK I ENGINE GROUND G100 B-80 EXHAUST GAS RECIRCULATION (EGR) • H T 39-.8 PNK/BLK I PCM (SEE PAGE 51) C 134 C 135 12H-25 12A3 12A5 1. 2. 3. 4. 5. 6. 1. RH Batteries 2. LH Battery 3. Starter Motor Figure 1 - Batteries and Cables (6.2L V8 HD Diesel Engine) Cold Advance Control Fast idle Solenoid Fuel Shut-Off Valve Generator Glow Plug (RH) Cold Advance and Fast Idle Temperature Switch Figure 2 - Engine Wiring Harness - RH Side (6.2L V8 HD Engine) COMPONENT LOCATOR VIEWS B-81 FRONT OF VEHICLE S116 VIEW [ a ] 1. 2. 3. 4. 5. 6. C106 Glow Plug Controller Water in Fuel Sensor Fuel Heater Back Up Lamp Switch Speed Sensor Oil Pressure Switch Figure 4 - Engine Wiring Harness - Rear (6.2L V8 HD Diesel Engine) FRONT OF VEHICLE C195 C100 C116 1. Glow Plug (LH) 2. Coolant Temperature Sender 1. 2. 3. Battery Junction Block Map Sensor Low Coolant Sensor 12H24 Figure 3 - Engine Wiring Harness - LH Side (6.2L V8 HD Diesel Engine) B-82 COMPONENT LOCATOR VIEWS Figure 5 - Engine Wiring Harness to Cowl/Radiator (6.2L V8 HD Diesel Engine) C117 FRONT OF VEHICLE 4 SPD., MAN TRANS 1. 2. 3. 4. 5. 6. Ignition Coil Distributor Electronic Spark Module Transmission Engine Temperature Switch Transmission Backup Lamp Switch 1. 2. 3. 4. 5. 6. 8. 9. Idle Air Control Actuator Injectors EVRV Starter Motor Knock Sensor TP Sensor Coolant Temperature Sensor Generator Map Sensor 12H22 Figure 6 - Engine Wiring Harness, LH Side (7.4L V8 Gas Engine) Figure 7 - Engine Wiring Harness, RH Side (7.4L V8 Gas Engine) COMPONENT LOCATOR VIEWS B-83 2 FRONT OF VEHICLE VIEW 1. 2. 3. 4. 5. 6. 7. 8. Map Sensor Idle Air Controller TP Sensor Injectors ESC Hybrid Knock Sensor Starter Motor EVRV Figure 9 - Engine Wiring Harness, RH Side (5.7L V8 Gas Engine) C118 C174 C108 C146 C185 4 SPD., MAN TRANS Coolant Temperature Sensor Coil Distributor Electronic Spark Module Oil Pressure Sender Output Speed Sensor Transmission Input Speed Sensor Engine Temperature Switch Vehicle Speed Sensor Backup Lamp Switch 12 Figure 8 - Engine Wiring Harness, LH Side (5.7 V8 Gas Engine) B-84 COMPONENT LOCATOR VIEWS 1. 2. 3. 4. 5. 6. 7. 8. Distributor Electronic Spark Module Oil Pressure Sender Output Speed Sensor Transmission Input Speed Sensor Knock Sensor Engine Temperature Switch C174 Figure 10 - Engine Wiring Harness to Cowl (7.4L V8 Gas Engine) 12H16 C110 cm C 112 GT101 S189 S190 1. 2. 3. 4. 5. 6. 7. 8. EGR Solenoid TP Sensor Injectors Starter Motor Map Sensor Coil Idle Air Control Coolant Temperature Sensor C206 C224 12C2 Figure 12 - Steering Column Switches S199 12H17 GlgO G101 FRONT OF VEHICLE FRONT OF VEHICLE G111 C116 C121 C115 VIEW B VIEW A Figure 11 - Engine Wiring Harness, RH Side (4.3L V6 Gas Engine) COMPONENT LOCATOR VIEWS B-85 C100 4.3L ENGINE S197 1. 2. 3. 4. Battery Junction Block Fuel Pump Relay ESC Hybrid Function Brake Pressure Warning Switch [¥ ] C113 (MAN TRANS ONLY) GT100 12H4 S109 G110 Figure 15 - Battery and Leads (4.3L V6 and 5.7L V8 Gas Engines W/ School Bus Equipment) G110 S101 G111 (5.7L ENGINE) VIEW (7.4L ENGINE) 1. 2. Battery Junction Block Fuel Pump Relay GT100 12H6 FRONT OF VEHICLE COMPONENT LOCATOR VIEWS Battery Starter Motor (4.3L ENGINE) VIEW B Figure 14 - Engine Wiring Harness to Cowl (4.3L V6, 5.7L and 7.4L V8 Gas Engines B-86 1. 2. Figure 16 - Battery and Leads (4.3L V6, 5.7L and 7.4L V8 Gas Engines) COMPONENT LOCATION Backup Lamp S w itc h ....................... . . Top LH front of tra nsm issio n ............................................. Battery, L H .......................................... . . LH front behind radiator s u p p o rt...................................... Battery, RH ........................................ . . RH front behind radiator support ................ ................... Battery Junction B lo c k ..................... . . RH side of shipping panel Brake Pressure Warning Switch . . . . . Cold Advance Control ..................... . . Cold Advance Fast Idle Temperature Switch ..................... . . Coolant Temperature Sensor (G asoline)........................................ . . Coolant Temperature Sensor (D ie s e l)............................................ , . . Distributor .......................................... . . .......................... ................... Near master cylinder ......................................................... Top front of e n g in e .......................................... ................... RH rear of e n g in e ........................................... ................... 81 2 Top front of e n g in e ........................................ ................... 83 7 Top RH front of e n g in e ................................. ................... Top rear of e n g in e ........................................ ................... 84 83 84 84 85 83 84 84 84 86 83 84 84 83 84 81 85 82 86 81 83 84 85 81 81 81 81 81 81 81 81 81 82 83 84 8 6 8 10 11 6 8 10 9 14 6 8 10 7 9 2 13 4 14 2 7 9 11 2 3 2 3 2 3 2 3 2 4 7 9 EGR Solenoid ..................................., . . Top RH side of e n g in e ................................. ................... Engine Temperature S w itc h ........... . . . LH side of e n g in e ........................................... ................... ESC H y b r id ....................................... . . . Top RH side of e n g in e ................................. ................... ESC Module Page - Figure 4 82 6 83 8 84 1 81 1 81 15 86 16 86 5 82 14 86 14 86 2 81 ..................................... . . . Top of engine at d istrib u to r.......................... ................... E V R V ................................................... , . . Top RH front of e n g in e ................................. ................... Fast Idle Solenoid ............................. . . Fuel Gage S e n d e r ............................. . . Fuel Heater ....................................... . . . Fuel Pump R e la y .............................. , . . Fuel Shut Off Valve ......................... . . . Generator (Diesel) ............................. . . Top LH side of engine ................................. In fuel t a n k ...................................................... Top rear of e n g in e ........................................ Top LH side of shipping panel ................... Top front of e n g in e ........................................ Front of e n g in e ............................................... ................... ................... ................... ................... ................... ................... Generator (Gasoline) ........................ . . Glow Plug #1 ................................. . . . Glow Plug # 2 ................................. . . . Glow Plug # 3 .................................... . . Glow Plug # 4 ................................. . . . Glow Plug # 5 ................................. . . . Glow Plug # 6 ................................. . . . Glow Plug # 7 ................................. . . . Glow Plug # 8 ................................. . . . Glow Plug Controller ..................... . . . Idle Air Control A c tu a to r................ . . . Front of e n g in e ............................................... LH side of e n g in e ........................................... RH side of e n g in e ........................................... LH side of e n g in e ........................................... RH side of e n g in e ........................................... LH side of e n g in e ........................................... RH side of e n g in e ........................................... LH side of e n g in e ........................................... RH side of e n g in e ........................................... Top LH rear of engine ................................. Top rear of e n g in e ........................................ ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... COMPONENT LOCATION Page - Figure Ignition C o i l ...................................... . . . Top of engine near d is trib u to r........................ ................. 83 84 85 . . . Top center of engine ...................................... ................. 83 84 85 . . . Top center of engine ...................................... ................. 83 84 85 Input Speed S e n s o r........................ . . . LH side of transmission ................................. ................. 84 84 . . . RH side of e n g in e ............................................. ................. 83 84 85 Low Coolant Sensor (Diesel) . . . . . . . RH side of ra d ia to r........................................... ................. 82 MAP Sensor (Diesel) ..................... . . . LH side of shipping p a n e l............................... ................. 82 MAP Sensor (Gasoline) ................. . . . Top rear of e n g in e ........................................... ................. 83 84 85 Oil Pressure Sender (D iesel)......... . . . Top rear of e n g in e ........................................... ................. 84 84 Oil Pressure Switch (Gasoline) . . . . . . Top LH side of tra n sm is sio n .......................... ................. 82 84 Output Speed Sensor ................... . . . LH side of transmission ................................. ................. 84 84 ................. 81 Starter M o t o r .................................... . . . Lower RH side of engine ............................... 83 84 85 86 86 TP Sensor ......................................... . . . Top RH side of e n g in e .................................... ................. 83 84 85 ................. 85 . . . LH side of steering c o lu m n ............................ Turn Signal S w itc h .......................... V S S .................................................... . . . Top LH side of tra n sm issio n .......................... ................. 82 84 Water in Fuel S e n s o r ..................... . . . Top rear of e n g in e ........................................... ................. 82 . . . LH side of steering c o lu m n ............................ ................. 85 Connectors: C100 ............................................. . . . Top left side of left cowl ................................. ................. 82 86 C102 ............................................. . . . Top left side of left cowl ................................. ................. 82 86 C103 ............................................. . . . At fuel pump relay ........................................... ................. 86 C105 ............................................. . . . At brake pressure warning s w itc h ................. ................. 86 C106 ............................................. . . . At coolant temperature sensor ..................... ................. 81 ................. 81 C107 ............................................. 83 84 85 COMPONENT LOCATER INDEX 6 8 11 7 9 11 7 9 11 8 10 7 9 11 5 5 7 9 11 8 10 4 8 8 10 1 7 9 11 15 16 7 9 11 12 4 8 4 12 5 14 5 14 14 14 3 2 7 9 11 B-87 COMPONENT LOCATION .......................... C108 ................................................ C109 ........................ .......................... C110 ........................ ..................................................... cm ................ ..................................................... C112 ........................ .......................... C113 ........................ .......................... C115 ........................ .......................... C116 ........................ .......................... C117 ........................ .......................... C118 ........................ .......................... C199 C120 C121 C125 ........................ .......................... ................................................ ..................................................... .................................................... ..................................................... .................................................... .................................................... C127 C128 C129 C130 C131 C132 C134 C135 C146 ......................................................................................................... C150 ......................................................................................................... B-88 .......................... ...................................................... ; ..................... .................................................... ......................................................................................................... .................................................... .................................................... ......................................................................................................... .......................................................................................................... .................................................... .................................................... Page - Figure 82 83 84 84 At coolant temperature sensor ............................... ___ 83 84 84 At throttle position s e n s o r ................................................................................. ______ 83 84 85 At RH in je c to r.............................................................. ___ 83 84 85 At LH in je c to r.............................................................. ___ 83 84 85 At ESC hybrid ........................................................... . . . . 84 86 At idle air control a c tu a to r......................................... ___ 83 84 85 At MAP s e n s o r ........................................................... ___ 82 83 84 85 At knock s e n s o r ......................................................... ___ 83 84 84 At oil pressure sender (gasoline) .......................... ___ 84 84 At oil pressure switch (d ie s e l)................................. ___ 82 At electronic spark m o d u le ............................................................................. ______ 83 84 84 At ignition coil ........................................................................................................................ ______ 83 84 85 LH side of distributor ................................................................................................ ______ 83 84 84 . . . . 85 At glow plug c o n tro lle r............................................. ___ 82 ______ 81 At water in fuel sensor ........................................................................................... ______ 82 At cold advance fast idle temperature switch . . . ______ 81 At fuel h e a te r ............................................................................................................................ ______ 82 Top of cold advance c o n tro l ........................................................................ . . . . 82 Fast idle s o le n o id .............................................................................................................. ______ 81 At backup lamp s w itc h ........................................................................................... ______ 82 83 84 At low coolant s e n s o r ................................................................................................ ______ 82 At engine temperature s w itc h ................................. COMPONENT LOCATER INDEX . . . . 5 6 8 10 7 8 10 7 9 11 7 9 11 7 9 11 9 14 7 9 11 5 7 9 11 7 9 10 8 10 4 6 8 10 6 8 11 COMPONENT LOCATION Page - Figure 83 84 84 83 84 84 83 84 84 83 84 82 84 86 81 81 81 81 81 81 81 81 85 85 85 85 85 6 8 10 6 8 10 6 8 10 7 9 4 8 14 3 3 3 3 2 2 2 2 12 12 13 13 13 LH lower side of c o w l............................................ ......... Center of injector b o d y .......................................... ......... 86 83 84 85 14 7 9 11 Top LH rear of engine 83 84 85 84 85 81 81 86 86 84 86 81 81 85 7 8 11 9 11 2 1 15 16 11 16 1 1 13 84 85 86 86 9 11 14 14 C172 ............................ ........................ LH center of transm ission..................................... ......... C173 ............................ ........................ Input speed sensor ............................................... ......... C174 ............................ ....................... Output speed s e n s o r ............................................ ......... C175 ............................ ....................... EVRV ........................................................................ ......... C185 ............................ C186 ............................ ..................... C192 ............................ ..................... C193 ............................ C194 ............................ ..................... C195 ............................ C196 ............................ ..................... C197 ............................ ..................... C198 ............................ C199 ............................ ....................... C206 ............................ ..................... C224 ............................ ..................... C400 ............................ ....................... C401 ............................ ....................... C402 ............................ ....................... Grommets: GT100 .......................... ....................... GT101 .......................... ..................... Grounds: G100 ............................. ..................... G101 ......... LH top of LH cowl (near support) ........................ ......... #1 glow p l u g .......................................................... ......... ......... # 5 glow p l u g .......................................................... ......... ......... # 2 glow p l u g .......................................................... ......... # 4 glow p l u g .......................................................... ......... ......... # 8 glow p l u g .......................................................... ......... Base of serving column ........................................ ......... Base of serving column ........................................ ......... At fuel t a n k ............................................................... ......... At fuel level s e n d e r................................................. ......... At rear lamp harness ............................................ ......... .......................................... ......... ............................ ..................... At alternator b ra c k e t............................................... ......... G102 ............................. ..................... G110 ............................ ..................... RH front top of engine .......................................... ......... RH side of radiator support above b a tte ry .......... ......... 6 8 10 11 4 2 G111 ............................ ......... G112 ............................. G113 ............................ G402 ............................. Splices: S 1 0 1 ............................... ......... ......... ......... S 1 0 2 ............................... ......... 4 2 4 4 2 4 6 ......... 8 5 COMPONENT LOCATION S 1 0 4 .......................................... S 1 0 9 .......................................... 5 11 1 511 2 511 3 511 4 511 5 511 6 511 7 S 1 8 9 .......................................... 5190 5191 5195 5196 5197 5198 S199 Page -- Figure Top LH side of c o w l........................................................... Top LH side of LH cowl .................................................... Top LH side of LH cowl .................................................... Top LH side of LH cowl .................................................... Front RH top of e n g in e ....................................................... RH top corner of e n g in e .................................................... RH top center of e n g in e .................................................... LH top rear of e n g in e ......................................................... RH top rear of e n g in e ......................................................... Top LH center of e n g in e .................................................... 86 86 86 86 81 81 81 81 81 83 84 84 85 Top LH side of engine ....................................................... 85 LH side of transmission .................................................... 83 84 LH side of cowl .................................................................. 82 86 LH side of cowl .................................................................. 82 86 LH side of cowl .................................................................. 82 86 Lower RH side of engine .................................................. 83 84 85 Lower RH side of engine .................................................. 83 84 85 14 14 14 14 2 2 2 3 2 6 8 9 11 11 6 8 5 14 5 14 5 14 7 9 11 7 9 11 COMPONENT LOCATER INDEX B-89 SECTION C P MODEL (MOTORHOME) SECTION C - P-MOTORHOME C-1 DRL RELAY (SEE PAGE 18) STEERING COLUMN SWITCHES FUEL PUMP SENDER (SEE PAGE 38) l/P CONNECTOR (SEE PAGES 4 BATTERY (SEE PAGES 4 REAR LAMPS HARNESS (SEE PAGE 61) PROVISIONS FOR WIPER/WASHER (SEE PAGE 28) REAR BODY CONNECTOR (SEE PAGE 38) C-2 PHANTOM VIEW SYMPTOMS INDEX SYMPTOM PAGE AUXILIARY COOLING FAN Auxiliary cooling fan does not r u n ................................................................................................................... C-48 Auxiliary cooling fan runs c o n tin u o u s ly .......................................................................................................... C-48 CRUISE CONTROL Cruise control does not disengage when brake pedal is depressed ...................................................... C-51 Cruise control does not operate ......................................................................................................................C-51 DIESEL ENGINE FUEL CONTROLS Service fuel filter indicator does not light briefly with ignition switch turned to RUN ............................ C-46 Fuel heater does not operate .......................................................................................................................... C-46 Water in fuel indicator lights with no water in fuel ....................................................................................... C-46 GAGES AND INDICATORS Fuel gage indicates full or beyond at all tim e s .............................................................................................. C-53 Fuel gage indicates empty when there is fuel in the ta n k ............................................................................C-53 Fuel gage is inaccurate ................................................................................................................................... C-53 Oil pressure gage indicates low pressure when oil pressure is g o o d ...................................................... C-53 Oil pressure gage indicates high pressure at all tim e s ................................................................................ C-54 Temperature gage indicates hot with engine coolant below operating temperature and ignition switch in R U N ................................................................................................................................................. C-54 Temperature gage indicates cold all the time .............................................................................................. C-54 Temperature gage is in a c c u ra te ..................................................................................................................... C-54 Low coolant indicator is lit when coolant level is g o o d ................................................................................ C-54 Low coolant indicator does not light with coolant level low (diesel o n ly ) ..................................................C-54 REAR EXTERIOR LAMPS None of the rear lamps operate ...................................................................................................................... C-60 Backup lamps do not o p e ra te ........................................................................................................................... C-60 START AND CHARGE Battery is undercharged or o v e rc h a rg e d ........................................................................................................ C-29 Engine does not crank and starter solenoid does not click ....................................................................... C-29 Starter solenoid clicks, engine does not crank or cranks s lo w ly ................................................................ C-29 TURN LAMPS Turn signals do not work on one s id e ............................................................................................................. C-23 Turn signals do not operate ..............................................................................................................................C-23 Turn signal lamps flash r a p id ly .........................................................................................................................C-23 WIPER/WASHER Wipers do not operate in any mode ............................................................................................................... C-27 Wipers do not operate in HI ..............................................................................................................................C-27 Wipers do not operate in L O ..............................................................................................................................C-27 GLOW PLUGS Wait indicator does not flash or flashes for the incorrect amount of time when engine is below normal operating te m p e ra tu re .......................................................................................................... C-43 HEADLAMPS Headlamps do not illuminate high or low beams - both sides .................................................................. C-13 Low beam lamp(s) do not operate .................................................................................................................C-13 High beam lamp(s) do not o p e ra te .................................................................................................................C-13 HEADLAMPS (WITH DRL) Headlamps do not illuminate high or low beams - both sides .................................................................. C-16 Low beam lamp(s) do not operate .................................................................................................................C-16 High beam lamp(s) do not o p e ra te .................................................................................................................C-17 Canadian daytime running lamps do not operate ....................................................................................... C-17 HORNS Horn will not operate ........................................................................................................................................C-25 Horn sounds continuously without depressing horn switch .......................................................................C-25 PARK, MARKER AND HAZARD LAMPS Park lamps do not o p e ra te ...............................................................................................................................C-21 Side marker lamp(s) do not o p e ra te ...............................................................................................................C-21 Hazard warning lamps do not operate .......................................................................................................... C-21 SYMPTOM INDEX C-3 _ _ _ _ _ _ _ 2-5.0 RED _ _ _ _. . ·P.iJ::' 2_ ow sr BAlTERY a:: o 2 • 0 44 START ~ 0 0 RUN OFF 0 1 lOCK . ._ _ _ _ _ _ 1-50.0 BlK C _L f- C201 I 6294641 ~ C200 12010966 ACC J 0 0 0 ;:: IGNITION COil (SEE PAGE 32) -' (L (L t 0 ~ aw Z Hi >:: z a:: ~ (L 0 0 N '9 ~ '" I S205 • AUTO APPLY PARK BRAKE SWITCH _ ..._ __ IGNITION SWITCH i·'"'"' ' _::::" 156 150 - DOME 2 OFF CIRCUIT BREAKER 25 AMP I LIGHT SWITCH I HEAD 10 PPNK STARTER MOTOR -- S100 .S103 • I~ ~~ a::rn S101 • , 40 _2-5.0 RED_ HEAD DIESEL 2-3.0 RED aw C202 12020029 a:: I~ o ~ PANEL DIMMER SWITCH om "'::J NbS 51 a:: o M N ~ • GT100 12085003 (UPPER) 12085002 (lOWER) a:: aw M o §».o o a:: ~ ~ S102 2-2.0 R S T _ • (FUSIBLE LINK) COOLING FAN RELAY (SEE PAGE 49) J -----JF i V yT I» ;r 11 I----- fcl-----*---- kH i ~BA~ ~ [g ~ ill ~ ~ rn:J rn:J ~ ill ~ ill 0 [ill ~ ~ AOCC 0 ~R jW: PWR r'i5flrstlnotl~ ~ ECM-BAT f""";;;-{l f10tl ~ ~ ~ L...r;J TAIL LPS m ~ HTR r::::l INJ ~ q 6 C! Z a:: rn ACC-RADIO r';;;;-;l M - o ~K ALT nsr.t G110 T~ DD n 0 CRNK k/S/PLR STOP-HAl 15AMP AlT 20 AMP ^TURN/BU TURN/BU * 115AMP 5 AMP ~n-otl~~ l.J.=W ~ AUX WIPER STOP-HAZ GASOLINE ENGINE OA GAUGES 0 LL"~- o I L.r;j INSTR-LPS L..r;J ~ HORN/OM POWER DISTRIBUTION ORN I ~ 0 [ill L Fsjn m C-4 2-5.0 RED _ _ _ __ ~~·-I-I C106 12045896 4i -m .1 ___ -.r-. =~OO-5.0 rn:Jrn:J~DillDD GENERATOR " ___11_ 9-1.0 BRN .300-5.0 ORN1 S201 a w I _ 10AMP WIPER 25 AMP INJ 7.5 AMP 2-5.0 RED 4 'Jj~'. _6-5.0PPL C201 o S200 • 44 START _2-5.0 RED RUN + + LH BATTERY RH BATTERY . .-.. ~ . -' 8: ~ w I 0. 0. '" 0 0 to W S150 _L 4-5.0BRN_ a: CD 0 ~ - p---------- a: o 0 N t -= -: -= ~1~ENG1NE ENGINE GROUND LH CYLINDER HEAD G113 ENGINE GROUND RH CYLINDER HEAD G112 0 0 D 9 508 331 E 35 8 397 3001301 sol G 39 1234 31 59 50 1 2 3 4 5 ;(; 12085003 (UPPER) 12085002 (LOWER) MI 10 OFF ,PARK z -----.....-- (]) o o [!!J S~5 - lID lID @ ill ~ CD [ill D C203 12020030 PANEL DIMMER SWITCH g w a: o to _ N L,.... 2-5.0 RED ~~i-i=r~~"o~ 0. 0. :b0 C202 12020029 ---., a: 2-3.0 RED o 12015764 -' 9-1.0BRN ----~- GAUGES 20AMP i_ TRANS 10AMP INSTR-LPS 5AMP A .l.BAT.l L l!!J @ !IJ ~ CD [ffi D L 3-3.0 P N K - , t D~ ACC ow a: o ..; N '~J IGN D~ HTR PWR ~OO~G ~OO~~ ~~~~ GAUGES PWR TRANS ECM-BAT INJ HTR ACC-RADIO l~~]K OAUXO WIPER HORN/OM INSTR-LPS TAIL LPS z '" a: Z 0. o o CD lID@@DOJDDO FUEL SHUT OFF VALVE (SEE PAGE 47) GENERATOR I 1 593 11 K 68 2501419 L 481 10 505 W/GASOLINE 901 93 75 NJ-l0 W/DiESEL l 1 /824T 141 4 p 10 9 8 7 6 12015964 a: q 0 ..; LIGHT SWITCH to 6 AJ- 2 150 24011111 439 17 2 ~~~~~~ID41-~==~~I[I:~~-~!~/P~--16 350 420 440 592 J • 3 [-J- J 3-3.0 PNK SHEET ./ METAL 0 , GROUND G110 :~:.:;E~RN-------. .~-·II-------3-5.0PNK-------. . ~, . '""-Z "-'"Z tri .., ..,tri oj Ir------------ .S100 ~ '-PARK HEAD GT100 W . CIRCUIT BREAKER 25 AMP ., C 140 15 120 GLOW PLUG CONTROLLER 2 40-+-.......- . "~l ow - DOME ...to 300-5.00RN 156 150 C! • • 0 (])~ I (FUSIBLE LINK) ACC HEAD 2-5.0 RED 2-1.0 RST _ _ _ __ IGNITION SWITCH z Z 0. 0 0 1 J 0. S101 • OFF [[ L.. .@::z' :;r., 2-2.0 RST (FUSIBLE LINK) -' 0 LOCK C200 12010966 906-.5 RST ----z~ (FUSIBLE LINK) ( 0 0 ...tri o w a: ..,tri a: o HORN/DM 15AMP o to 6 g HTR Lb.~11.1 ECM-CRNK 10AMP ~~~OO ST P- .T U R N /B U 15 A M P ALT CRNK ~ PuS/P~ 10AMP WIPER 25 AMP POWER DISTRIBUTION DIESEL ENGINE C-5 — €< 0) 1-50.0 BLK d. I I /n r .-------- y If [ GT100 12085003 (UPPER) 12085002 (LOWER) COOLING FAN RELAY (SEE PAGE 48) SHEET METAL GROUND G110 C-6 POWER DISTRIBUTION GASOLINE DRIVEAWAY INJECTORS 7.5 AMP ECM 10 AMP IGN 20 AMP I 6-5.0 PPL 1-32.0 BLK I J" r^3— + RH BATTERY + [ □ □ b e [M o LH BATTERY IGNITION SWITCH -^=r 300*5.0 ORN | DIESEL ONLY E ONLY | G ASO LINE ONLY 3-3.0 PNK 3 9 | 1 » 4 3 1 1Y59 ! 50 I ! 300 30 P 50 I 35 397-j*----- !--------9 508 140 15 120j«-----j--------7 1 4i- fl 33 2 481 W /G ASOLINE o ( , N |1 5 0 | 2 4 0 |1 1 1 |/ G ASO LINE O NLY 250 419 .... 593 11 |4 2 0 |4 4 0 | 592 I 439 f 17 I 2 DIESEL ONLY 10 W /DIESEL J 2 3 140 9 35 ! 150 | 240 |111| I 14 3 9 1 17 I 2 | 16 |3 5 0 | | I 14 2 0 1440 I 592 15 120 593 11 — I /"-\ L _ 68 250 419 508 33 O i— 8 397 ^ 10 505 ^ I 19011 93 75 [300 30 | 50 I | |824| 14 4 39 11234 3 1 1 59 | 50 | | 5 10 l/P S -481 W /G ASO LINE ■10 W /D IESEL 12015964 — I 3-3.0 PNK ■ VAM AW W W VVV^ % HOT IN START OR RUN ? V W W W W V W A ^C ECM 10 AMP REAR __ r in h f| o r h © d h c ] [ ] c ] t —] o S I ■CD- DS on FUSE BLOCK 12052472 BOT £5 ENGINE GROUND LH CYLINDER HEAD G113 ENGINE GROUND RH CYLINDER HEAD G112 POWER DISTRIBUTION DIESEL DRIVEAWAY C-7 1 L WE:lu ED u fB L GO HI 0 0 ; e m □ ACC IGN □ □ CD O KC> r BAT 11 8-1.0 GRA- I 1— 1 □ 350-.8 PNK/WHT - FUEL CYC MDL o 300-5.0 ORN - IGNITION □ □ HTR PW R 0 □ GXA UI 1PW 30,R1 1 G ES tK ] I _ Xi _ K 1 d c TRANS E C M -B A T K l' £ INJ3 KHTR] 30A~1 B“ ] K l S T O P -H A Z E C M -C R N K o 20A ALT K ] TURNm i AUX SHUNT 12041235 8-.8 GRA - INSTRUMENT LAMPS 8-1.0 GRA--------------------------------------------- 300-5.0 ORN - IGNITION H O RN /D M IN S T R -L P S TA IL L P S 240-1.0 ORN - HORN RLY - DOME LAMP 250-1.0 BRN - TRANSMISSION 440-1.0 ORN - ECM 2-5.0 RED - BATTERY - 50-3.0 BRN 44-1.0 DK GRN - LT SW RHEOSTAT 40-1.0 ORN - TAIL LAMPS 481-1.0 RED - INJECTORS -141-1.0 BRN/WHT 4-5.0 BRN - IGN SW K l A C C -R A D IO 93-3.0 WHT - WINDSHIELD WIPER DW IPd ER 140-1.0 ORN - STOP LAMP SW - HAZ FLSHR 439-1.0 PNK/BLK - ECM (FUSED) 76-3.0 PNK - AUXILIARY 0C R N K0 16-.? PPL - TURN SIGNAL SW 75-.8 DK BLU - BACK-UP LAMP SW □ □ FU S/PLR 3-5.0 PNK - IGNITION 3-5.0 PNK - IGN SW - ENG IGN 39-.8 PNK/BLK - INSTRUMENT CLUSTER 39-1.0 PNK/BLK - ALTERNATOR - EGR SOLENOID FRONT 12034359 - BLOCK MOLD 12089776 - PRINTED BLOCK -38-.8 DK BLU - TURN SIGNAL C-8 COLOR MALE CONN A BRN 12004887 B BLK 12004886 H GRN 12004885 1 NAT 12004888 L BLU 12004884 FUSE BLOCK GASOLINE ENGINE FU SE L O C A T IO N FU SE P A R T NO. COLOR AND AM PERE HOT C O N D IT IO N R A D IO A C C E S S O R IE S HTR 12004010 W H IT E 25 A M P H O T IN RUN H O T IN R U N O R START ALTERNATO R IN J 12004006 BRN 7.5 A M P HO T IN R U N O R START GRN 30 A M P H O T IN R U N O R STA RT B O D Y B U IL D E R IN S T A L L E D A C C E S S O R IE S IN S T R -L P S 12004005 TA N 5 AMP H O T W/ H E A D L A M P IN PARK O R HEAD 12004007 RED 10 A M P HO T AT A L L T IM E S E L E C T R O N IC C O N T R O L M O D U L E S T O P -H A Z 12004008 LT B L U E 15 A M P H O T AT A L L T IM E S STOP LAM PS HAZARD FLA SH ER E C M -C R N K 12004007 RED 10 A M P H O T IN R U N O R STA RT PW R C IR C U IT BREAKER GRN 30 A M P H O T AT A L L T IM E S B O D Y B U IL D E R IN S T A L L E D A C C E S S O R IE S G AUGES 12004009 YELLO W 20 A M P H O T IN RUN P R O V IS IO N S F O R G A G E S T A IL L P S 12004009 YELLO W 20 A M P H O T AT A L L T IM E S TA IL L A M P S H O R N -D M 12004008 LT B L U E 15 A M P H O T AT A L L T IM E S P R O V IS IO N S F O R HORN AND DOME LAM PS TRANS 12004007 RED 10 A M P HOT IN R U N O R ST A R T T R A N S M IS S IO N TURN-B/U 12004008 LT B L U E 15 A M P HOT IN R U N O R START T U R N S IG N A L S B A C K -U P L A M P S W IP E R 12004010 W H IT E 25 A M P HO T IN A CC O R RUN FU SE L O C A T IO N FU SE P A R T NO. COLO R AND AM PERE HOT C O N D IT IO N A C C - R A D IO 12004007 RED 10 A M P H O T IN A C C O R RUN ALT 12004009 YELLO W 20 A M P AUX C IR C U IT BREAKER E C M -B A T D E S C R IP T IO N E L E C T R O N IC C O N T R O L M O D U L E IG N IT IO N 1 D E S C R IP T IO N H EATER IN J E C T O R S IN S T R U M E N T P A N E L L A M P S W IN D S H IE L D W IP E R S 8-1.0 G RAI— □ x c > 1 n iT A 0 [L ]P tD 0 W i i 0 □ ® □ m ® □ m IG N □ □ HTR PW R □ [§] @] ACC IshV n t ] II n r s i K l E l K ] □ 0 [jd KTRANSl 25A INJ u§] STOP-HAZ ECM-CRNK ° 1 | 30A | 44-1.0 DK GRN - LT SW RHEOSTAT 40-1.0 ORN - TAIL LAMPS ECM-BAT D 3 HTR ACC-RADIO 30A DWIPER §] AUX ALT D d 240-1.0 ORN - HORN RLY - DOME LAMP SHUNT 12041235 8-.8 GRA - INSTRUMENT LAMPS 8-1.0 G R A --------------------------------------------- G AUG ES HORN/DM INSTR-LPS TAIL LPS b 140-1.0 ORN - STOP LAMP SW - HAZ FLSHR '439-1.0 PNK/BLK - ECM (FUSED) 3-5.0 PNK - IGN SW - ENG IGN 39-.8 PNK/BLK - INSTRUMENT CLUSTER CRNK □ □ 39-1.0 PNK/BLK - ALTERNATOR - EGR SOLENOID TURN-B7U FUS/PLR FRONT 12034359 - BLOCK MOLD 12089776 - PRINTED BLOCK 38-.8 DK BLU - TURN SIGNAL- COLOR MALE CONN A BRN 12004887 B BLK 12004886 H GRN 12004885 1 NAT 12004888 L BLU 12004884 FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION HTR 12004010 WHITE 25 AMP HOT IN RUN ALTERNATOR INSTR-LPS 12004005 TAN 5 AMP HOT W/ HEADLAMP IN PARK OR HEAD BODY BUILDER INSTALLED ACCESSORIES STOP-HAZ 12004008 LT BLUE 15 AMP HOT AT ALL TIMES STOP LAMPS HAZARD FLASHER PWR CIRCUIT BREAKER GRN 30 AMP HOT AT ALL TIMES BODY BUILDER INSTALLED ACCESSORIES TAIL LPS 12004009 YELLOW 20 AMP HOT AT ALL TIMES TAIL LAMPS PROVISIONS FOR GAGES TRANS 12004007 RED 10 AMP HOT IN RUN OR START TRANSMISSION PROVISIONS FOR HORN AND DOME LAMPS TURN-B/U 12004008 LT BLUE 15 AMP HOT IN RUN OR START TURN SIGNALS BACK-UP LAMPS WIPER 12004010 WHITE 25 AMP HOT IN ACC OR RUN FUSE LOCATION FUSE PART NO. COLOR AND AMPERE HOT CONDITION ACC-RADIO 12004007 RED 10 AMP HOT IN ACC OR RUN RADIO ACCESSORIES ALT 12004009 YELLOW 20 AMP HOT IN RUN OR START AUX CIRCUIT BREAKER GRN 30 AMP HOT IN RUN OR START ECM-BAT 12004007 RED 10 AMP HOT AT ALL TIMES ECM-CRNK 12004007 RED 10 AMP HOT IN RUN OR START GAUGES 12004009 YELLOW 20 AMP HOT IN RUN HORN-DM 12004008 LT BLUE 15 AMP HOT AT ALL TIMES DESCRIPTION ELECTRONIC CONTROL MODULE ELECTRONIC CONTROL MODULE IGNITION 1 DESCRIPTION HEATER INSTRUMENT PANEL LAMPS WINDSHIELD WIPERS FUSE BLOCK DIESEL ENGINE C-9 LAMP BULB DATA AC Type Guide Lamps are recommended when replacement becomes necessary. Lamp Usage Headlamp1 Quantity 2 Trade No. Power Rating at 12V, Watts 6014 50/60 W Candle Power LAMP BULB DATA 2 2057 32-2 Tail and Stoplamp3 (Union City Body Co.) 2 1157 32-3 Tail and Stoplamp2 (Except Union City Body Co.) 2 2057 32-2 Front Side Marker Lamp 2 194 2 Rear Side Marker Lamp 2 194 2 License Lamp 2 67 4 Backup Lamp4 — — — Instrument Cluster Illumination Lamp 6 PC194 2 Turn Signal Indicator Lamp 2 PC194 2 Headlamp High Beam Indicator Lamp 1 PC74 .7 Service Brake Warning Indicator Lamp 1 PC74 .7 Park Brake Warning Indicator Lamp 1 PC74 .7 Transmission Control Illumination Lamp 1 73 .3 Low Coolant Indicator Lamp5 1 PC74 .7 Glow Plug Indicator Lamp5 1 PC74 .7 Water in Fuel Indicator Lamp5 1 PC74 .7 Service Engine Soon Indicator Lamp 1 PC74 .7 Trans Indicator Lamp5 1 PC74 .7 Fasten Safety Belts Indicator Lamp6 1 PC74 .7 Door Ajar Indicator Lamp 1 PC74 .7 Daytime Running Lights Indicator Lamp7 1 PC118 .7 1. 2. 3. 4. 5. 6. 7. C-10 Park and Signal Lamp2 Double filament sealed beam: 50W low beam, 60W high beam. Double filament lamp: 32 CP high, 2 CP low. Double filament lamp: 32 CP high, 3 CP low. Refer to body manufacturer’s specifications. Diesel only. When used by body manufacturer. Canada only. RPO CODES T61 - CANADIAN DAYTIME RUNNING LAMPS p I 4 3 9 1 17 I 2 1150 I 240 11111 A I | 16 350| B 3 14 2 0 1440 C 140 15 120 593 250 D 9 508 33 8 397 ^ 10 505 E 35 w 19011 93 F 1300 30 I 50 I I | 59 | 50 | | 14 G 39 11234 31 1 2 3 4 5 10 9 7 J — N J-------- -J S113 ^ A/C COMPRESSOR I 413-. 8 TAN I __ 68 8 1454-.8 BLK/WHT I PCM (SEE PAGE 34) COOLING FAN PRESSURE SWITCH (SEE PAGE 49) L n CM CO (SEE PAGE 50) PCM (SEE PAGE 34) _ /~N ALDL (SEE PAGES 35, 37) ■ 450-.8 BLK/WHT ) PCM ■ 450-.8 BLK/WHT I (SEE PAGE 34) 2 592 11 419 75 4 6 H l/P J K L .481 W /G ASOLINE M ■10 W /D IESEL N' P 12015964 DIESEL ONLY G ASO LINE ONLY | -G A j ? LINE ONLY ,481 W /G ASOLINE “ 10 W /D IESEL r ----------------1 /ti rrs::: S 112 l/P CLUSTER (SEE PAGE 56) ■ 150-1.0 BLK PANEL DIMMER SWITCH 1 150-3.0 BLK (SEE PAGE 58) GT 100 CD CO 12085003 (UPPER) 12085002 (LOWER) CD CO DRL MODULE (T61 ONLY (SEE PAGE 18) WIPER SWITCH L _____- « (SEE PAGE 28) DRL RELAY (T61 ONLY) (SEE PAGE 18) DRAC (SEE PAGE 42) ENGINE GROUND G102 ENGINE GROUND G100 ALTERNATOR BRACKET GROUND G103 l/P GROUND G200 FRAME GROUND G400 GROUND DISTRIBUTION GASOLINE ENGINE C-11 ^ 150-.8 BLK ALDL (SEE PAGE 41) DRAC (SEE PAGE 42) 150-.8 BLK I WIPER SWITCH (SEE PAGE 28) 1150-.8 BLK I GLOW PLUG CONTROLLER (SEE PAGE 47) PANEL DIMMER DRL RELAY (SEE PAGE 18) GT100 1150-. 8 BLK I WATER IN FUEL SENSOR 12085003 (UPPER) 12085002 (LOWER) (SEE PAGE 47) EF71 1150-.8 BLK I FUEL HEATER (SEE PAGE 47) 551-1.0 TAN/WHT TCM (SEE PAGE 41) I 450-1.0 BLK/WHT r 150-.8 BLK 1150-.8 BLK I p i i —. i i 2 115 0 I 240 11111 A J439 i 1 7 I | B 3 I 16 |350| | | 14 2 0 1440 C 140 15 120 593 - J L _ D 9 508 33 68 250 E 35 8 397 ^ 10 505 ^ F 1300 30 | 50 | | {901| 93 G 39 1234 3 1 1 59 | 50 | | | 824) 14 1 2 3 4 5 10 9 8 7 ------- v -------- 4 i 5 1 2 3 G 3 9 | 1234 F 30 P 50 E 35 D C 140 B 16 I3 5 0 f 2 ^ 150 I 24011111, 311^591501 C-12 GROUND DISTRIBUTION DIESEL ENGINE G108 ENGINE GROUND , |824| 14 ENGINE 481 W /G ASOLINE I G ASO LINE ONLY 9* G109 SHEET METAL GROUND O 75 4 6 r\ H l/P J K L .481 W /G ASOLINE M N | ■10 W /DIESEL P 12015964 DIESEL ONLY G ASO LINE ONLY | GASO LINE ONLY 2 £ G101 ENGINE GROUND 2 592 11 419 O I I 10. ■■*1iA ,-----^ Z Z 1 > 8 250 419 L 593 11 K |420| 440 | 592 J t 4 3 9 1 17 I 2 H "T T 10 W /D IESEL DIESEL ONLY G200 l/p GROUND HIGH BEAM LAMP(S) DO NOT OPERATE CIRCUIT OPERATION TEST Voltage is applied to the Light Switch at all times. The Light Switch includes a Self-Resetting Circuit Breaker. The Circuit Breaker opens when the Headlamp circuit draws too much current. When the Circuit Breaker opens, it interrupts the current flow. With no current flow, the Circuit Breaker cools off and resets automatically. When the Light Switch is in HEAD, the Headlamp Dimmer Switch directs voltage to either the Low Beams or the High Beams. The Hi Beam Indicator also receives voltage along with the High Beams. 1. 2. DIAGNOSIS - HEADLAMPS HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS - BOTH SIDES RESULT TEST 3. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from light switch connector C202 to battery junction block. 2. With the light switch on and the headlamp dimmer switch to HIGH BEAM, connect a test lamp from YEL (10) wire at light switch connector C202 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. 3. Test lamp lights. REPAIR open LT GRN (11) wire from headlamp dimmer switch connector C215 to connector C101. Test lamp does not light. REPLACE headlamp dimmer switch. ACTION Test lamp does not light. GO to step 2. Test lamp lights. ISOLATE problem in body builder’s installed wiring. Place headlamp dimmer switch in HIGH BEAM position. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. GO to step 3. Test lamp lights. LOCATE and REPAIR open in LT GRN (11) wire from headlamp dimmer switch connector C215 to connector C101. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire at headlamp dimmer switch connector C215 to light switch connector C202. Test lamp lights. REPLACE headlamp dimmer switch. Place light switch to ON and headlamp dimmer switch to HIGH BEAM position. Connect a test lamp from LT GRN (1.1) wire at connector C101 to ground. ACTION 1. Connect a test lamp from RED (2) wire at light switch connector C202 to ground. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C215 to ground. RESULT LOW BEAM LAMP(S) DO NOT OPERATE TEST RESULT ACTION 1. Turn the light switch to ON and headlamp dimmer switch to LOW BEAM position. Connect a test lamp from TAN (12) wire at connector C101 to ground. Test lamp does not light. GO to step 2. Test lamp lights. ISOLATE problem in body builder’s installed wiring. 2. Connect a test lamp from TAN (12) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. GO to step 3. Test lamp lights. LOCATE and REPAIR open in TAN (12) wire from headlamp dimmer switch connector C215 to connector C101. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire from headlamp dimmer switch connector C215 to light switch connector C202. Test lamp lights. REPLACE headlamp dimmer switch. 3. HEADLAMPS BASE C-13 RH SIDE MARKER LAMP HORN u C137 12004267 1 15-.5 DK BLU • S121 I 11-1.0 LTGRN S122 LH HIGH-LOW HEADLAMP NOTE: THIS H A R N E SS IS SHIPPED ALONG WITH THE VEHICLE AND IS INSTALLED BY THE BODY BUILDER. LH SIDE MARKER LAMP G107 C-14 FORWARD LAMP HARNESS G106 SHEET METAL GROUND G105 FRAME Q j GROUND G104 BATTERY JUNCTION BLOCK 9 0 0 0 C101 12059472 o FORWARD LAMP HARNESS y REAR LAMP HARNESS (SEE PAGE 62) I l/P CLUSTER 111-1.0 LT GRN I (SEE PAGE 56) I 11-1.0 LT GRN ■ ■ ■ C203 14(M 15 120 _ J 9 # 5 0 8 33 — n 35 [ 8 397 ^ ^ L_ O ^ 39 11234 3 1 1 59 j 50 | 5 593 11T 68 250 419 10 505 A [82 4 j 14 12020030 W /G ASOLINE PANEL DIMMER SWITCH 10 W /DIESEL 2015964 10 DIESEL ONLY G ASO LINE ONLY | ^GASO LINE ONLY ENGINE 9 I 50 | 50 | T \ i 824i 14 I o —1 3 HEADLAMP DIMMER SWITCH | 16 13501 150 I 2 4 0 11 T l]/ G ASO LINE ONLY 481 W /G AS O U N E 1 [59 |4 2 0 |440 1439) 1 7 j DIESEL ONLY 150- 3 I I P . 505L use iil 2 10 W /D IESEL - OFF m I ■ 156 DOME CIRCUIT BREAKER 25 AMP 12015113 »PARK HEAD I 10-1.0 YEL I I 11-1.0 LT GRN I LIGHT SWITCH OFF 'PARK 40' HEAD LIGHT SWITCH HEADLAMPS BASE C-15 CIRCUIT OPERATION LOW BEAM LAMP(S) DO NOT OPERATE TEST CANADIAN DAYTIME RUNNING LAMPS Relay. When energized, the DRL Relay disconnects the DK BLU/WHT (593) wire from ground and internally connects it to the ORN (240) wire, causing it to be 12 volts. Battery voltage is applied to the Daytime Running Lamps (DRL) Relay Switch at all times through the BRN (50) wire and the HTR fuse. With the Headlamps on, the DRL Relay is not energized and the LT BLU/ORN (593) wire is grounded to BLK (150) wire inside of the relay. This serves as ground for the LH Headlamp. With Ignition in RUN, headlamps off and Park Brake released, the DRL Module applies battery voltage to the LT GRN/BLK (592) wire. This action illuminates the DRL Indicator in the Instrument Panel and energizes the DRL The DK BLU/WHT (593) wire feeds the LH High Beams which are connected in series to the RH Headlamp through the LT GRN (11) wire. Grounding of the entire DRL circuit is accomplished through the BLK (151) wire at the RH Headlamp. This result in High Beam headlamps that are less intense for daytime driving and should provide longer service. DIAGNOSIS - HEADLAMPS (WITH DRL) RESULT 1. Turn light switch ON and headlamp dimmer switch to LOW BEAM position. Connect a test lamp from TAN (12) wire at connector C101 to ground. Test lamp does not light. GO to step 4. Test lamp lights. GO to step 2. 2. Test lamp does not light. LOCATE and REPAIR open in DK BLU/WHT (593) wire at connector C101 to DRL relay connector C208. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE DRL relay. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire from DRL relay connector C208 to ground G200. Connect a test lamp from TAN (12) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. GO to step 5. Test lamp lights. LOCATE and REPAIR open in TAN (12) wire from headlamp dimmer switch connector C215 to connector C101. If no open is found, ISOLATE problem in body builder’s installed wiring. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C215 to ground. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire from headlamp dimmer switch connector C215 to light switch connector C202. Test lamp lights. REPLACE headlamp dimmer switch. 3. 4. Connect a test lamp from DK BLK/WHT (593) wire at DRL relay connector C208 to ground. Connect a test lamp from BLK (150) wire at DRL relay connector C208 to ground. PRELIMINARY CHECKS: HIGH BEAM LAMP(S) DO NOT OPERATE test procedures. If the High Beam Lamp(s) are operative, use the following diagnostic procedures, after placing the Light Switch to OFF position. Before checking the DRL system, do the following: 1. Place Park Brake in the OFF position. 2. Place Light Switch to ON and Headlamp Dimmer Switch to HIGH BEAM position. If the High Beam Lamp(s) are inoperative, refer to the HEADLAMPS DO NOT ILLUMINATE HIGH OR LOW BEAMS - BOTH SIDES TEST RESULT Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from light switch connector C202 to fuse block. 2. With the light switch on and the headlamp dimmer switch to HIGH BEAM. Connect a test lamp from YEL (10) wire at light switch connector C202 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. 3. Test lamp lights. REPAIR open in LT GRN (11) wire from headlamp dimmer switch connector C215 to connector C101. Test lamp does not light. REPLACE headlamp dimmer switch. Connect a test lamp from LT GRN (11) wire at headlamp dimmer switch connector C215 to ground. C-16 HEADLAMPS W/DRL 5. ACTION Connect a test lamp from RED (2) wire at light switch connector C202 to ground. 1. ACTION CANADIAN DAYTIME RUNNING LAMPC I LOW BEAM LAMP(S) DO NOT OPERATE TEST Turn light switch ON and headlamp dimmer switch to LOW BEAM position. Connect a test iamp from TAN (12) wire at connector C101 to ground. Test lamp does not light. GO to step 4. Test lamp lights. GO to step 2. Connect a test lamp from DK BLK/WHT (593) wire at DRL relay connector C208 to ground. Test lamp does not light. LOCATE and REPAIR open in DK BLU/WHT (593) wire at connector C101 to DRL relay connector C208. Connect a test lamp from BLK (150) wire at DRL relay connector C208 to ground. Connect a test lamp from TAN (12) wire at headlamp dimmer switch connector C215 to ground. Connect a test lamp from YEL (10) wire at headlamp dimmer switch connector C215 to ground. TEST ACTION RESULT Test lamp lights. GO to step 3. Test lamp does not light. REPLACE DRL relay. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire from DRL relay connector C208 to ground G200. Test lamp does not light. GO to step 5. Test lamp lights. LOCATE and REPAIR open in TAN (12) wire from headlamp dimmer switch connector C215 to connector C101. If no open is found, ISOLATE problem in body builder’s installed wiring. Test lamp does not light. LOCATE and REPAIR open in YEL (10) wire from headlamp dimmer switch connector C215 to light switch connector C202. Test lamp lights. REPLACE headlamp dimmer switch. 1 2, 3. 4 5 With ignition in RUN, headlamps off and park brake released, connect a test lamp from ORN (240) wire at DRL relay connector C208 to ground. Connect J 34029-A Multimeter from BRN (50) wire at DRL module connector C217 and DRL relay connector C208 to ground. Measure voltage. Connect J 34029-A Multimeter from BRN (50) wire at DRL module connector C217 and DRL relay connector C208 to BLK (150) wire at each component connector. Measure voltage. Connect J 34029-A Multimeter from LT GRN/BLK (592) wire at DRL relay connector C20§ to ground. Measure voltage. Connect a test lamp from DK BLU/WHT (593) wire at connector C101. NOT OPERATE RESULT ACTION Test lamp does not light LOCATE and REPAIR open in ORN (240) wire between DRL relay connector C208 and fuse block or REPLACE HORN/DM fuse. Test lamp lights. GO to step 2. Battery voltage at only one connector. LOCATE and REPAIR open in BRN (50) wire between splice S211 and connector with missing voltage. No battery voltage at eithc connector. LOCATE and REPAIR open in BRN (50) wire between splice S211 and fuse block or REPLACE HTR fuse. Battery voltage at both connectors. GO to step 3. No voltage. LOCATE and REPAIR open in BLK (150) wire between suspect connector and ground G102 or G200. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in LT GRN/BLK (592) wire between DRL relay connector C208 and DRL module connector C217. If no open is found, REPLACE DRL module. Battery voltage. GO to step 5. Test lamp does not light LOCATE and REPAIR open in DK BLU/WHT (593) wire between DRL relay connector C208 and connector C101. If no open is found, ISOLATE problem in body builder’s installed wiring. Test lamp lights. DRL are operating. HEADLAMPS W/DRL C -1 7 y W M A /W W v / BATTERY JUNCTION BLOCK < V A A M /W W V W 'M HOT A T A L L TIMES C < >vWVVWVVV\N HOT IN START OR RUN Z W /M A M W V W 'C HTR 15528797 25 AMP ~ . . . ._ _ _ _ _ _ _ _• 50·2.0 BRN _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _• o o o o ~.2.1.0RST ~ (FUSIBLE LINK) . ._ _. . . . . ._ _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240.1.00RN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . • S100 I 0 w a: 0 • Iri i l>ClJocm."c;> _ _ _ _ _ _ _ _ _ _ _ 2-5.0 REO _ _ _ _ _ _ _ _ _ _ _~N eN CQ ~ ~ '" ...L ..... ..... ~~Q~Lj~------- 2·3.0 RED _ _ _ _ _ _ _ _. , . U;~Q)~NN (II 0) ~t:-:- 0 ~~ 1 ~~l.o- )"1 :111 1_ . ._ _ _ _ _ _ l"'.OLTGRN . . . . . . . . . . . ._ . . . . . . . . . 11·1.0LTGRN _ . . . . . . . . . . . . I ~ • _________________ °WNt1~www :g 0t- ... ~~-----. 24O·1.00RN _ _ _ _ _ _ _ ~ ~~SL~LINE ",1$ '" 0 GASOLINE ONLY !:::::::. '-:: _1 ......._ .. 50·3.0 BRN -----~~~~y~~;:~t GASOLINE 0 DIESEL ONLY .1 ..._ _ _ _ 10·1.0YEL _ _ _ _ , ,_ _ 10·1.0YEL _ r .1_ ,/~ -.J """11_ _ _ _ _. . 24O.1.00RN f- DIESEL ONLY :g1en - ....- _ _ _ _ 50.3.0BRN _ _ _ _ _ _ __ I,.. ONLY ____ - .... ....- --....-... 1 f- _ : 593·.8 DK BLU/WHT I--' - .... ~f i 593-.8 DK BLU/WHT ,,~;7=~ ..-__.. _ ... 150.1.0BLK. . . . . . . . . . . . _:=- _ ~ , I , '" _1··S2.1.S_ _ _ _.11•.1•.0LTGRN ~ _ _ _ _. . . ._ _ _ _ '" - 0 0 12-.8 TAN til l> • C-18 l.QJ ~Oh - W/DRL ~ Cl0l , ,""Mn G102 t- :: _ _ _ _ _ _ _ 11-1.0 LT GRN _ _ _ _ _ _ _. . HEADLAMPS m o -FORWARD LAMP HARNESS ENGINE GROUND • • _ _ _ _.150•. 8BLK . ._ _ _ _ _ _ _ _ _. . • , -_ _ _• r11 24O.1.00RN 24O•2.0 0RN . . . . 24O-1.00RN _ . ~ '" 50-3.0BRN _ _ _. . C208 12052287 592-.8LTGRN/BLK HORN RELAY (SEE PAGE 26) 240-1.0 ORN _ _. . . ._ _ ....-... _ _ _ 593-.8DKBLU/WHT _ _ _ _ ........J /~rr~I?~r'~ . ._ _ S214 (SEE PAGE 18) , _ _...... • _ _ _ _ _ _ _ _ _ _ _ _ _ _ 12•. 8TAN _ _ _ _ _......... • _______ • • ~,- ... 593-.8 DK BLU/wHTr L,. _ _ _ .. 592.. 8LTGRN/BLK _ _ _ _ _ _ _ _. : (SEE PAGE 11) , l 1 . 0 L T G R N - - - - - - -. . . . . ,_____________________ ::::::~:~R.N S204 , . • i ..___________________~I~------.I-,, 1_________ • 1_._ . • _12 •. 8TAN _ _ _ _ _ _ _ _ _ _ _ _ _ _ ...~ , q ......+~ ................................ I ffi ,~ S112 (SEE PAGE 11) . _. ._ _ _ _ 150.2.0BLK-, - ....-... _ :......_ _ _ 10-1.0YEL _ _ _ _ _ _ _ __ ENG 12015113 ~ , 33-.5 TAN/WHT _ 2 4 0 + - -_ _-, 50 ....._ _--. 593 592 _ DRL RELAY 150-+-----.... l/P CLUSTER CONNECTOR (SEE PAGE 55) DOME LAMP (SEE PAGE 59) DRL MODULE I 2*3.0 RED i I 240-1.0 ORN I I 50-3.0 BRN I I 33-. 5 TAN/WHT I 110-1.0 YEL I ' 593-.S DK BLU/WHT , i n - 1.0 l t g r n m am * 592-.0 LT GRN/BLKI 1 12-.8 TAN | LIGHT SWITCH LIGHT SWITCH IQ) l/P GROUND G200 HEADLAMPS C-19, W/DRL | 0 RH SIDE MARKER LAMP HORN 151 12077765 11-1.0 LT G R N * RH HIGH-LOW HEADLAMP C137 12004267 12-.8 TAN I ID _J CO * ■ 15-.5 DK BLU 15-.8 DK BLU * ■ 29-1.0 DK GRN RH PARK AND TURN LAMP ,• S121 593-.S DK BLU/WHT 14-.5 LT BLU I1 2 -.8 TAN ■ 9-.8 BRN LH PARK AND TURN LAMP I 11-1.0 LTG RN S122 11-1.0 LT GRN | 12-.8 TAN LH HIGH-LOW HEADLAMP 593-.8 DK BLU/WHT 151-3.0 BLK 14 L 0 C141 12077765 C-20 FORWARD LAMP HARNESS W/DRL NOTE: THIS HARNESS IS SHIPPED ALONG WITH THE VEHICLE AND IS INSTALLED BY THE BODY BUILDER. LH SIDE MARKER LAMP G105 SHEET METAL GROUND G104 FRAME Q ) GROUND SIDE MARKER LAMP(S) DO NOT OPERATE CIRCUIT OPERATION RESULT TEST PARK AND MARKER LAMPS 1. Voltage is applied through the TAIL LPS Fuse to the Light Switch at all times. With the Light Switch in PARK or HEAD, voltage is applied to the Park, Tail, Marker, and License Lamps. The Front Marker Lamps are grounded through the LH and RH Park and Turn Lamps. HAZARD LAMPS Voltage is applied at all times through the STOP-HAZ Fuse and the Hazard Flasher to the normally open contact of the Hazard Switch in the Turn Signal Switch. With the Hazard Switch in HAZARD FLASH, voltage is applied to both Front and Rear Turn Lamps. All of the Turn Lamps and both Turn Indicators flash on and off. The Front Marker Lamps flash in HAZARD FLASH just as they did in TURN RIGHT and TURN LEFT, if the Lamp switch is in OFF, they flash on when the Hazard Lamps are on. If the Lamp Switch is in either PARK or HEAD, they flash on when the Hazard Lamps are off, and off when the Hazard Lamps are on. In HAZARD, the circuit is always open, and the Hazard Flasher Controls the Lamps. DIAGNOSIS - PARK, MARKER AND HAZARD LAMPS PRELIMINARY CHECKS: If only one lamp is inoperative, inspect wire(s) to affected lamp socket, check bulb-to-socket fit or replace bulb. Place light switch in PARK position. Connect a test lamp from BRN (9) wire at connector C101 to ground. (See page 15 for wiring of marker lamp circuit.) ACTION Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. LOCATE and REPAIR open in BRN (9) wire from connector C101 to light switch connector C202. HAZARD SIGNAL LAMPS DO NOT OPERATE RESULT TEST 1. Place ignition switch in RUN and position turn signal lamps as if making a turn. 2. Turn off turn signal lamps and put hazard warning lamps ON. Connect a test lamp from BRN (27) wire at turn signal switch connector C211 to ground. ACTION Turn signal lights operate. GO to step 2. Turn signal lights do not operate. REFER to "Turn Signals Do Not Work On One Side" symptom. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. CHECK condition of STOP/HAZ fuse and for an open in ORN (140) wire and BRN (27) wire. If fuse and wiring are good, REPLACE hazard flasher. PARK LAMPS DO NOT OPERATE TEST RESULT ACTION 1. Place light switch in PARK position. Connect a test lamp from ORN (40) wire at light switch connector C202 to ground. (See page 15 for wiring of park lamp circuit) Test lamp lights. GO to step 3. Test lamp does not light. GO to step 2. 2. Test lamp lights. CHECK condition of TAIL LPS fuse. If fuse is good, LOCATE and REPAIR open in ORN (40) wire. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire from fuse block to battery junction block. Connect a test lamp from BRN (9) wire at light switch connector C202 to ground. Test lamp lights. GO to step 4. Test lamp does not light. REPLACE light switch. Connect a test lamp at BRN (9) wire at connector C101 to ground. Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. LOCATE and REPAIR open in BRN (9) wire from connector C101 to light switch connector C202. 3. 4. Connect a test lamp from RED (2) wire at fuse block to ground. PARK, MARKER AND HAZARD SIGNAL LAMPS C-21 STOPLAMP SWITCH (CLOSES WHEN WHEN (CLOSES BRAKE PEDAL PEDAL BRAKE IS DEPRESSED) DEPRESSED) IS < , 140 liP CLUSTER CONNECTOR HOT A T A L L TIMES C m vw w w w s STOP-HAZ 15 AMP (SEE PAGE 55) C218 12040744 (STEERING COL SWITCHES) C216 2984235 I 17-1.0WHT z a: 0 C! - - --,.. ~ I• ~ _ _ _ _ _ _ _ 140-.100RN _ _ _ _ _ _ _ _ 1 ~ 18-1.0YEL --~~~;F=n P 17 16-.8 PPL _ _ _ _~~~Iy~ N 19 27-1.0 BRN _ _ _~ M 18 L 16 S210 I 14-.5 LT BLU - HAZARD FLASHER . ._ _ 17-1.0 WHT _ _- ' C212 2973385 z __• ___ 27-1.0 BRN W~--..- - . 140-1.0 OR N a: ---~W:!rLJ 27 27-1.0 BRN J 15 15-.5 DK BLU H 14-.5 DK BLU G 28-.5 BLK 6 ;:: 12004147 - .8 LT GR N - t-~c>:L -s. 'KEvT p _____________________ 15-.5DKB 2 H 5 11 K 1~.J.:;4""'2::J0'T'4"'4"&'~59::"'2,..l J 0 I I I I 10 110 901 824 9 8 5 9 14 7 liP LU WIGASOLINE ~ MI 75 NTlO WIDIESEL 46 P 12015964 . ._ _ _ _ _ _ _ _ 15-.5 D( B LU . ._ _ _ _ _ _ 14-.5 LT B ..________.1_ _ _____ 16-.8 PPL LU - Cl00 12015113 10 '\9 I r T\ 0 D 9 508 331 C 140 15 12~~5QL:::t-1 B A r1W,ollll]1 ~ -] 'r ---=::;Z68 25.19 5931111 420 440 IS I 439 17 2Il r H ~ 8 7 6 824 14 4 901 9:l1 75 10 50 -- - P ENG N 481 MIIU)W/GASOLINE L K -- ~10WIDIESEL J H 12015113 ~\ w ,~ _ _ _ __ g C « (!l _ _ _ _ _ _.19-1.0 DK GRN --- ----- - E _ _ _ _ _ _ _ 140-1.0 OR D C ~ 17-1.0WHT B A • ---II- 12020926 . ._ _ _ _ _ _ _ _ _ _ _ 14-.5 LT BLU _ _ _ _ _ _ _ _ _ _ _ _. . A B _ _ _ _ _ _ _ _ _ 140-1.00RN _ _ _ _ _ _ _ _ __ 1GT100 12085003 12085003 (UPPER) (UPPER) 12085002 (LOWER) (LOWER) 12085002 HAZARD SIGNAL LAMPS 12020786 C400 12065158 . .- - - - - - - - - - - - 15-.5 DK BLU C-22 REAR LAMP HARNESS 19-1.0 DK GRN 17-1.0 WHT _ _ _ _ _ _ _ _ _ 16-.8 PPL _ _ _ _ _ _ _ _ _ _• ~ F . ._ _ _ _ _ 15-.5 DK BLU _ _ _ _ _• • ~~ • N ---------:~~iiC~D~ FORWARD LAMP HARNESS Cl0l 12059472 I ~fi!;'S PRNDL LAMP (SEE PAGE 58) ....... - - - 8-.5 GRA _ . _ _ _ _ _ _ _ 18-1.0 YEL DIESEL ONLY GASOLINE ONLy'l GAS~LlNE ONLY 1 2 3 \. 4 l5 G 39 1234 311159 50 300 30 50 F E 35 8 397 LU . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 14-.5 LTB ~+6:;842;11+4",1..:;9LL::..!-481 I TURN SIGNAL SWITCH .1 7 -= 12004148 . ._ _ _ _ _.14-.5 LT BLU _ _ _ _ _ _ 439 § I- I ~, HORN I A 1 240 111 B 3 11 350 C 140 15 120 D 9 508 33 E 35 8 397 F 300 30 I 50 I G 39 12341 311 59 I 50 1 2 3 4 5 S2 a: I I _ _ _ _ _ _.15-.5 DK BLU _ _ _ _ ~~~~~~~~~~~~~~- t;: ~ NORMALLY OPEN SWITCHES 112~. 0 C! .rr-I 18-1.0YEL 16-.8 PPL K F E 0 14-.5 LT BLU ~~rl 17-1.0WHT 19-1.0 DK G RN TURN SIGNALS DO NOT OPERATE CIRCUIT OPERATION TEST TURN SIGNAL LAMPS 1. With the Ignition Switch in RUN or START, voltage is applied through the TURN/BU Fuse and Turn Flasher to the normally closed contact of the Hazard Flasher Switch in the Turn Signal Switch. With the Turn Signal Switch in LH Turn position, voltage is applied to both the LH Turn Indicator and the LH Front Park and Turn Lamp LT BLU (14) wires. Voltage is applied to the LH Tail, Stop and Turn Lamp YEL (18) wire.' The Lamps go on immediately. They begin to flash when the current flow heats up the Timing Element in the Flasher and it repeatedly opens and closes the circuit. The voltage applied to the LH Park and Turn Lamp will also be applied to the LH Side Marker Lamp. If the Lamp Switch is in the OFF position, the LH Side Marker Lamp will find a path to ground through Splice S123 and the Park and Turn Lamp to ground. This Lamp provides low resistance paths to ground. The Marker Lamps will flash with the Turn Lamps. When the Light Switch is in either PARK or HEAD, voltage is applied through the TAIL LPS Fuse, Lamp Switch, and Splice S122 to the Marker and Park Lamps. If the Turn Signal Switch is in TURN LEFT, the LH Side Marker Lamp will have voltage at both connections and will go out. When the Flasher removes voltage to the Turn Lamp, the Marker Lamp will be grounded through the Turn Lamp and will go on. In this way, the LH Side Marker Lamp will flash on when the LH Park and Turn Lamp goes off, and off when the Turn Lamp goes on. Place hazard warning lamps to ON position. 2 . Connect a test lamp from PPL (16) wire at turn signal switch connector C211 to ground. DIAGNOSIS - TURN LAMPS ACTION Hazard lamps operate. GO to step 2 . Hazard lamps do not operate. REFER to "Hazard Lamps Do No Operate" symptom. Test lamp lights. REPLACE turn signal switch. Test lamp does not light. CHECK condition of TURN/BU fuse and for an open in PPL (16) wire or DK BLU (38) wire. If fuse and wiring are good, REPLACE turn signal flasher. TURN SIGNAL LAMPS FLASH RAPIDLY TEST 1 . Turn hazard lamp switch to ON With the Turn Signal Switch in TURN RIGHT, voltage will be applied to the RH Lamps in the same way. RESULT position. Check from turn signal lamps and rear taillamps. RESULT ACTION One side of turn signal lamps flash rapidly. REPLACE inoperative turn signal bulb. Only one side of turn signals light but do not flash rapidly. REFER to “Turn Signals Do Not Work On One Side" symptom. TURN SIGNALS DO NOT WORK ON ONE SIDE TEST RESULT ACTION Lights flash. CHECK for improper bulb. REPLACE if necessary. Lights do not come on. GO to step 2. 2. Turn hazard warning system off. Place ignition switch to RUN and turn signal to side that does not work. Connect a test lamp from LT BLU (14) or DK BLU (15) wire (depending upon which side does not work) at turn signal switch connector C211 to ground. Test lamps lights. GO to step 4. Test lamp does not light. GO to step 3. 3. Connect a test lamp from PPL (16) wire at turn signal switch connector C211 to ground. Test lamp lights. REPLACE turn signal switch. Test lamp does not light REPLACE turn signal flasher. Connect a test lamp from LT BLU (14) or DK BLU (15) wire (depending on which side did not work) at connector C101 to ground. Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. LOCATE and REPAIR open in either LT BLU (14) or DK BLU (15) wire(s) between turn signal switch connector C211 and connector C101. 1. Turn hazard warning system on. Observe lights on side of turn signals that did not work. 4. TURN SIGNAL LAMPS C-23 ~BA~ ~ I1l ~ [0 [ffi 0 L lID lID ~ ill ~ [0 0 [ffi [ID[ID~D[oOD ACC liP CLUSTER CONNECTOR o (SEE PAGE 55) IGN HTR PWR C218 12040744 ~DD~EJ GAUGES TURN SIGNAL SWITCH PWR [}DOO[}D~ TRANS ECM-BAT HORN/OM INSTR-LPS (STEERING COLUMN SWITCHES) OODDOO~ TAIL LPS INJ HTR ACC-RADIO 1 I 00 0000 0 [}§J [}§J 30A STOP-HAZ ECM-CRNK ALT AUX WIPER CRNK T~ ~spQ 19-1.0DKGRN 17-1.0WHT P -----~If19]iB N M _ ....-:;:-1....., r-~-+-16 18-1.0 YEL 16-.8 PPL L K ------t--+---t..... +-_....J . - - -_ _ 27-1.0 BRN J ...J W p----_____________ >~ 16-.8 PPL L-...._+-38 • D . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ 15-.5 DK BLU _ _ _ _ _ • t-....1...f'=Cr'JlI:o'-r""2'='! H 592 J 3 11 K 0419 L 5 MI 75 N 4 P 6 2 _ _ _ _ _ _ _ _ _ _ _ _ 14-.5 LT BLU _ _ _ _ _ liP 15-.5 DK BLU 481 W/GASOLINE 14-.5 LT BLU - 10 W/DIESEL 12015964 Cl00 G F E 15-.5 DK BLU _ __ _ _ _ _ _ _ _ _ _ _ 14-.5 LT BLU _ _ _ _. . TURN FLASHER 1 H JIIlII'I"":::"+rr" 16-.8 PPL ~ 1_ 12004147 C211 12004148 OPEN SWITCHES 1_ - ---- PRNDLLAMP (SEE PAGE 58) . . - 8-.5 GRA 19-1.0DKGRN F 18-1.0YEL E D C ~ 42 439 7 6 4 4 3 75 50 5 25 0419 59 3 11 4 o 592 7 2 B P N ENG 481 W/GASOUNE ~ Mild) ~Vl0 W/DIESEL J H L"'l 12015113 I~ DIESEL ONLY L • _ _ _ 15-.5 DK BLU . ._ _ _ _ _ _ _ _ _ 16-.8 PPL C-24 TURN SIGNAL LAMPS c:::s:::: r~ J[ 14-.5 LT BLU 1- - .18-1.0 Y E L r A Cl02 "" 19-1.0 DK GRN_ C400 12065158 12020786 14-.5 LT BLU _ _ _ _ _ _ _ _ _ _ _ _ _- . 15-.5 DK BLU _ _ _ _ _ _ _ _ _ _ _ _ _. . GT100 12085003 (UPPER) 12085002 (LOWER) FORWARD LAMP HARNESS Cl0l 12059472 CIRCUIT OPERATION When the Horn Switch is depressed, one side of the Horn Relay coil is grounded. The relay is energized. Its contacts close and battery voltage is applied to the Horns. DIAGNOSIS - HORNS PRELIMINARY CHECKS: Check to see that the HORN/DM fuse is not blown. REPLACE if blown. HORN W ILL NOT OPERATE TEST 3. 4. ACTION Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. GO to step 2 . Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in ORN (240) wire between horn relay connector C207 and fuse block or REPLACE HORN/DM fuse Reinsert horn relay. Disconnect turn signal switch connector C211. Connect a jumper wire to BLK (28) wire at turn signal switch connector C211 to ground. Horn does not sound. GO to step 4. Horn sounds. REPLACE horn switch. Disconnect horn relay. Install a jumper wire from ORN (240) terminal to DK GRN (29) terminal at horn relay connector C207. Horn sounds. REPLACE horn relay. Horn does not sound. LOCATE and REPAIR open in DK GRN (29) wire from horn relay connector C207 to horn. If no open is found, ISOLATE problem in body builder’s installed wiring. 1. Connect a test lamp from DK GRN (29) wire at connector C101 to ground. Press horn switch. 2. RESULT Remove horn relay. Connect a test lamp from ORN (240) wire at horn relay connector C207 to ground. HORN SOUNDS CONTINUOUSLY WITHOUT DEPRESSIN G HORN SWITCH RESULT TEST 1 . Disconnect turn signal switch ACTION Horn stops. REPLACE horn switch. Horn continues to sound. GO to step 2. No shorts found. REPLACE relay. Short(s) found. REPAIR or REPLACE as required. connector C211. 2. Disconnect horn relay connector C207. Check for a short to ground in BLK (28) wire. HORN C-25 y v w /w w v w > HOT AT ALL TIMES C > V W W V V \V \A T A HORN/DM } 15 AMP * HORN RELAY C 207 12065169 2 G C o I 240-1.0 ORN I 17 PROVISIONS FOR DOME LAMP (SEE PAGE 59) 19 17-1.0 WHT ■ 19-1.0 D K GRN 18 „ 18-1.0 YEL [ 16 - 16-.8 PPL 27 ^ 27-1,0 BRN 15-.5 DK BLU 15 X - 14-.5 LT BLU 14 HAZARD - 28-. 5 BLK I I 8 3 | 16 13 5 0 1 140 15 120 — 9 508 33 — n 35 8 397 ^ 1300 30 | 50 39 11234 3 1 1 59 | 2 3 | | O w | 50 ] 5 ■v | |420[ 4 4 0 ! 593 L _ 68 250 r— 10 505 | |901| 93 | (8 2 4 |1 4 592 11 419 75 4 I 12004147 C211 12004148 .481 W /G ASO LINE TURN SIGNAL SWITCH 10 W /D IESEL 10 12015964 8-.5 g r a prndl LAMP (SEE PAGE 58) C100 12015113 DIESEL ONLY I n==r' o 2 G C O DRL RELAY ^ ■ ■ I ^ H I GT100 240-1.0 ORN S214 HORN lr 240-1.0 ORN (SEE PAGE 18) C-26 L 12085003 (UPPER) 12085002 (LOWER) A B C D 29-1.0 DK GRN FORWARD LAMP HARNESS WIPERS DO NOT OPERATE IN LO CIRCUIT OPERATION TEST WIPER circuit is through the PPL (92) wire, the Wiper/Washer Switch and the BLK (150) wire to ground. The W iper Motor is supplied battery voltage with the Ignition Switch in START or RUN, with ground supplied by the Wiper/Washer Switch. Place ignition in RUN and wipers to LO. Connect a fused jumper from GRA (91) wire at wiper switch connector C207 to ground. RESULT Wiper motor does not run. LOCATE and REPAIR open in GRN (91) wire between wiper motor connector C150 and wiper switch connector C207. If no open is found, REPLACE wiper motor. Wiper motor runs. REPLACE wiper washer switch. WASHER When the Wiper Motor is in LO, battery voltage is supplied to the motor through the WHT (93) wire and the ground circuit is through the GRA (91) wire. Battery voltage is applied to the washer pump through the WHT (93) wire, to the switch and to ground through the BLK (150) wire. The washers are operational as long as the paddle switch on the Wiper Switch arm is on. When the wiper is in HI, battery voltage is supplied to the motor through the WHT (93) wire and the ground ACTION DIAGNOSIS - WIPER/WASHER PRELIMINARY CHECKS: Check condition of WIPER and INST LPS fuses. If fuses are in good condition, use the following diagnostic procedures. WIPERS DO NOT OPERATE IN ANY MODE TEST 1. Place ignition in RUN and turn wipers to HI. Connect a test lamp from WHT (93) wire at wiper motor connector C150 to ground. 2. Connect a fused jumper from BLK (150) wire at wiper switch connector C207 to ground. RESULT ACTION Test lamp does not light. LOCATE and REPAIR open in WHT (93) wire between wiper motor connector C150 and fuse block. Test lamp lights. GO to step 2. Wiper motor runs. LOCATE and REPAIR open in BLK (150) wire between wiper switch and ground G102 (Gasoline) or G101 (Diesel). Wiper motor does not run. REPLACE wiper motor. WIPERS DO NOT OPERATE IN HI TEST 1. Place ignition in RUN and wipers to HI. Connect a fused jumper from PPL (92) wire at wiper switch connector C207 to ground. RESULT ACTION Wiper motor does not run. LOCATE and REPAIR open in PPL (92) wire between wiper motor connector C150 and wiper switch connector C207. If no open is found, REPLACE wiper motor. Wiper motor runs. REPLACE wiper washer switch. WINDSHIELD WIPERS/WASHERS C-27 HOT IN A C C Y O R RUN WIPER 25 AMP L 93-3.0 WHT I A 2 150 124011111 B 3 i 16 1350} | C 140 15 120 — ^ D 9 508 33 r n E 35 8 397 ^ ^ F 1300 30 | 50 | G 39 1234 31 ! 59 | 50 | 1 2 3 4 5 | | | 11 17 i I' BOI 440 \ 1593 L _ % 250 ^ 1»505 n | |9 0 ir 9 3 | |824f 14 10 9 8 7 2 H 592 J 11 K 419 L 75 4 6 l/P .481 W/GASOUNE M Nl •10 W/DIESEL P 12015964 C100 194*1.0 PNK I WIPER MOTOR (BODY BUILDER INSTALLED) 192-1.0 PPL* ■97-1.0 LT BLU I ■ 91-1.0 GRAh 12015113 DIESEL ONLY GASOUNE ONLY I GASOLINE ONLY H \ 1 10 3911234 31 |« iT 5 0 l 35 8 397J 9 508 33 140 15 120 o 2 [150 I 240|111|/ GASOUNE ONLY ■93-3.0 WHT l DIESEL ONLY |^H150-.8 BLK* ■ 15Q-.8 B LK * • M 150-1.0 BLK S112 (SEE PAGE 12) 150-1.0. BLK ■ I PULSE WIPER CONTROL MODULE S204 (SEE PAGE 11) 97 GT100 12085003 (UPPER) 12085002 (LOWER) ENGINE GROUND G102 (GAS) G101 (DIESEL) C-28 WINDSHIELD WIPERS/WASHERS 1150-.8 BLKI 94 T B= i . J C207 12020492 C204 PULSE WIPER, WASHER SWITCH (COLUMN MOUNTED) 8 ENGINE „ 481 W/GASOLINE .. 1824114 I I 1flW 505 — — 419 I Jr 1593 11 A»n i # 3 9 1 17 D IE9fl ONLY I 2 m> 10 W/DIESEL ENGINE DOES NOT CRANK AND STARTER SOLENOID DOES NOT CLICK CIRCUIT OPERATION RESULT TEST START contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off. When the Ignition Switch is moved to the START position, battery voltage is applied to the Starter Solenoid. Both solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the Starter Motor. The windings work together magnetically to pull in and hold in the Plunger. The Plunger moves the Shift Lever. This action causes the Starter Drive Assembly to rotate as it engages the Flywheel ring gear on the engine. At the same time, the Plunger also closes the solenoid switch contacts in the Starter Solenoid. Full battery voltage is applied directly to the Starter Motor and it cranks the engine. CHARGE The Generator provides voltage to operate the vehicle’s electrical system and to charge its Battery. A magnetic field is created when current flows through the Rotor. This field rotates as the Rotor is driven by the engine, creating an AC voltage in the Stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the Battery terminal. As soon as the Solenoid Switch contacts close, voltage is no longer applied through the Pull-In Winding, since battery voltage is applied to both ends of the windings. The Hold-ln Winding remains energized, and its magnetic field is strong enough to hold the Plunger, Shift Lever, and Drive Assembly Solenoid Switch contacts in place to continue cranking the engine. When the Ignition Switch is released from the START position, battery voltage is removed from the PPL (6) wire and the junction of the two windings. Voltage is applied from the Motor contacts through both windings to ground at the end of the Hold-ln Winding. However, the voltage applied to the Pull-In Winding is now opposing the voltage applied when the winding was first energized. The magnetic fields of the Pull-In and Hold-ln Windings now oppose one another. This action of the windings, with the help of the Return Spring, causes the Starter Drive Assembly to disengage and Solenoid Switch This Generator’s regulator uses digital techniques to supply to Rotor current and thereby control the output voltage. The Rotor current is proportional to t h e width of the electrical pulses supplied to it by the Regulator. When the Ignition Switch is placed in RUN, narrow width pulses are supplied to the Rotor, creating a weak magnetic field. When the engine is started, the Regulator senses Generator rotation by detecting AC voltage at the Stator through an internal wire. Once the engine is running the Regulator varies the field current by controlling the pulse width. This regulates the Generator output voltage for proper battery charging and electrical system operation. The digital regulator controls the VOLTS Indicator light with a solid-state light driver. The light driver turns on the light whenever undervoltage, overvoltage or a stopped Generator is detected. ACTION 1. Place transmission in PARK. Connect a voltmeter from PPL (6) wire at starter solenoid to ground. Turn ignition switch to START position. Battery voltage. GO to step 2. No voltage. GO to step 3. 2. Connect a voltmeter from PPL (6) wire to starter mounting bolts. Battery voltage. REPLACE starter solenoid. Less than battery voltage. CLEAN starter motor mounting bolts, starter motor, and mounting surface. Battery voltage. REPLACE ignition switch. No voltage. LOCATE and REPAIR open in RED (2) wires and fusible link between ignition switch connector C200 and battery junction block. 3. With ignition switch in OFF position, connect a voltmeter from RED (2) wire at ignition switch connector C200 to ground. STARTER SOLENOID CL CKS, ENGINE DOES NOT CRANK OR CRANKS SLOWLY TEST RESULT ACTION 1. Connect a voltmeter to positive and negative battery terminals. Turn ignition switch to START. 2. Connect a voltmeter from negative battery terminal to engine block. 3. Connect a voltmeter from positive battery terminal to starter solenoid terminal to BLK (2) wire. Voltage reading greater than 9.5 volts after 15 seconds cranking. GO to step 2. Voltage less than 9.5 volts after 15 seconds cranking. PERFORM a Battery Load Test. Refer to Section 6D in 1991 R/V, P Light Truck Service Manual. Less than .5 volts. GO to step 3. More than .5 volts. REPLACE negative battery cable. Less than .5 volts. REPAIR starter motor. More than .5 volts. REPLACE positive battery cable. DIAGNOSIS - START AND CHARGE BATTERY IS UNDERCHARGED OR OVERCHARGED RESULT TEST 1. Connect a voltmeter from RED (2) wire at generator to ground. 2. Connect generator connector C105 and terminal. Have all accessories turned off and engine running at fast idle. Connect voltmeter from battery terminal on generator to ground. ACTION Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in RED (2) wire and fusible link from generator to battery junction block. Reading of 13-16 volts. PERFORM Generator Bench Test. Refer to Section 6D in 1991 R/V, P Light Truck Service Manual. Reading of less than or greater than 13-16 volts. REPAIR generator. STARTING/CHARGING C-29 idd o‘Q-9 I I i qbu o'9-z ECM-BAT 1 0 AMP ------*4—X -----k-ai—■. ki ■■■»■■ p* k. im yC I h .....L i / 1„| ■ '-----J t — -a -a « -a • g s a - l CRUISE CONTROL MODULE (SEE PAGE 52) G110 C-30 STARTING/CHARGING GASOLINE ENGINE 4 4 0 -.8 O R N I „TCM (SEE PAGE 40) l/P CLUSTER (SEE PAGE 56) ENGINE GROUND LH CYLINDER HEAD G113 ENGINE GROUND RH CYLINDER HEAD G112 FUSE BLO C K (SEE PAGE 4) STARTING/CHARGING DIESEL ENGINE C-31 ECM-CRNK 10 AMP I 1439-1.0 PNK/BLK I 439-1.0 PNK/BLK I423-.8 WHT, I430-.8 PPiyW HT 1424-.8 TAN/W HT H -------------- ■453-.S BLK/RED ' C125 12015791 12010996 P424-.8 T A N /W H T I ! L i. I -.8 W H T i Lr ^!4 2 4 -.8 TAN/W HT — 4 4 5 3 -.8 BLK/RED C121 12040705 J430-.8 PPL/WHT I ^ * 1 3-5.0 PNK | GT100 DISTRIBUTOR 12085003 (UPPER) 12085002 (LOWER) I1 2 1 -.8 W H T | wmmmm S205 I i i - (SEE PAGE 4) \ f f a r • jm m r i ^ i 4 3 9 - . s p n k / b lk m h t I 3-5.0 P N K i (SEE PAGE 4) SPLICE S202 (SEE PAGE 19) ■439-1.0 PNK/BLK I -1 GE] o oo fO cn Ul (0 o « £ ti W Z ::; ,. ~ • - - , .............. CD ~ '" e ~ -- ............................ , ,, - - - - - - - ..., ,.-- - I ~ 0 w Z ~~ ~~+...:::.=--, .Je" w U> w i5 ~ - ,-,-, ... >J~ ~r ~ ,. 0 c 1 2450,.. 440 .455 3~"'~ 452 474 496 451 4~ 5 @Q] 417 6 00 7 rngJ OB~ o 9 [ffi] 010~ ~1100 .i= -= ~I.. ~120 @§ID 13 413 @Q] 14 f.illl .. j ,. . 1- r ~ ~15[@ '. -- I ~, 2:J C250 12052177 412-.& PPL • PCM CONNECTORS 413-.BPPL _ _ _ _ _ _ 439-.&PNKlBLK ... ~ c::::J 1 1226 2 1225 3 1 24 @Q] 5 0 6 ~7 ~e 1230 ---....,.--• ~ Z • ~ It) o L - -- -- I _----- , ~ .. '" ~ 'lllll1IGIQJ 16 [§1J o w 0 ..,.-~ -_... , 1.225-.8 OK BLU _ _ _ _ _ 413-.& PPL Z U> ...,-. ... 'II1II ,- "1- I 1224-.& PNK 44O-.BORN ::; ~, 1230-.& OK BLU/wHT .......... . ._ _ _ _ 440-.& ORN _ _- . 439-.B PNK/BLK - , I , _~_ -_ ... , ....... 1227-.& BLK/YEL 1226-.8 RED _ . ., .........- F . - 451-.&WHT/BLK _ _ _ _ 4~~~::::L ............... 1 - _1226-.8RED_,_ ~,. 45O-.BBLKlWHT· _ _ _ _ _ _ _ _ _ _ _ _ ..-454-.&BLKlWHT _ _ 417-.& OK BLU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 &DKBLU 44O-.&ORN ",'_455-.BPPL - 474-.8 GRA 496-.&DKBLU _ , _ , ... - GT100 416-.&GRA _ . _ ,~ 454-.& BLKlWHT .. -l- ,-,- 45Q-.& BLKlWHT A w z ::; C251 12052175 o U> ~ ALDL C204 12020043 -c ... . .- - 59-.& OK GRN - - - -... AIR CONDITIONING (SEE PAGE 50) POWERTRAIN CONTROL MODULE (PCM) INPUTS - GASOLINE ENGINE C-35 ·I-::::::::::::::::::::::::::::::::::::::::::::::::~~:~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::---""": L ~ r" ,...., ~ ~ ----. ~ ~ ,...., a. .... ~ 442 ~ A ,. . , ,. . , - - ,...., ,...., , . . . . , , . . . . , . . . " , . . . . , , . . . . , . . . . . , ~ ~ ,. . , .-., . ." 1 ,...., ~ ~ ~ ~ ~ 442-.8DKGRN/BLK - ,...." .... ~ ... 441-.8 DK GRN/WHT ... ~ B ,...., ... 443-.8DKBLU/WHT ~ . . " , ... ,. · =- - ..." _ Slll ~ ~ -"," .... ..." _ ~ 450-.8 BLK/WHTF ,'~ ~ ~ ~ 'I. , , , .. .. 444-.8 DK BLU/BLK 12047951 . .- - - - - - - - - - - - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ~ - - ~ - ..." . . . " ,...., - ~~ - ~ ~ ~ - ~ - ~- - IIiIo ...... • ...--..... ~ _ ...... .. . . 439-.8 PNK/BLK . . . . . . • - --- , ~ " ' I F - - . . . . ." - - C C C 44O-.80RN 120-.8 GRA - . - 423-.8WHT - - - 453-.8BLK/AED· ........ 424-.8TAN/WHT F , I-,~· B 439 ...., ~ :J ---I ..... _ ,...., .....,,...., ,...., ,...., .--..... ...-..... , . ...--t . . .......... ,....,' .... ___ ....,,....,,....,......... , .... -I ... ,. . _ . . _ ...... ,rr ~--,. ;- - - -t:.:~:.:,.:,:..::~:,:. : ='::~~""--: ,-,, ' ,-, ___________________ ·..." .-., . . . . .... 1'I - .... - . -..-- - .-1,....,· ...... r , "--1-I - - . - ......-,:,-...... ~ - • ..." ---...... .... ....1,. - ..." ~, :c . ·-1-1-. .-1_,_:-,',. r.'=-:'::t':!r _:1- __ ""G"_,_ c 0 435 ~,....,,...., 450-.8BLK/WHT ___ ,...., ~ ~ ~ . , IDLE AIR • CONTROL III ACTUATOR 0 EVRV ~ ~ . .- - - - - - - - - - - - - - 44O-1.00RN _ _ _ _ _ _ _ _ _ _ _ _. . . 450 ..." ..." ,....,,...., rir..." ...". .",....,,...., - ,...., ...,. . , 250-1.0BRN ,....,,...., ,...., ~ ~ 439-1.0PNK/BLK . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 44O-1.00RN , 43O-.8PPL/WHT --C ..-..c A C120 12078082 ~ ",F .-~ ... ~ ,...., • • •,. .... _465-.8DKGRN/WHT .......... 1228-.8BLK/AED ELECTRONIC SPARK TIMING 423 EST SIGNAL 430 EST REFERENCE PULSE HI 424 453 EST BYPASS EST REFERENCE PULSE LO ~-,,..,-,-, _ 430-.8 PPL/WHT_ . _ 424-.8 TAN/WHT_ ,422-.8TAN/BLK ... _467-.8DKBLU-l . . B _ 453-.8 BLK/RED... .... r-- GROMMET 0112 12020549 101 12084618 INJ-2@:~~~ INJ-1 @~: ..._ _ _ _ 468-.8 DK GRN _ _ _ _I INJ-2 INJ-1 I I I S109 r.~:r71rn~~~------120-'8 GRA - - _ . _ •••••••••••••••••••• : itIII---44O-·80RN-----L..-_ _ _- - ' Cl18 0 I I -44O-.80RN- 111.. ....., - F , to .-- , ..., • • • _ _• l'" ~_ ..J I :'~tr 12~90 ~ "'442-.8DKGAN/BLKF . . ...... 441-.8DKGRN/WHT_k ..... • • • 1222-.8LTGAN_ ...... ,"'_.,,.,, ,_1= . ~ i • ... 443-.8DKBLU/WHT . . . . . . . _ . - . , .... 444-.8 DK BLU/BLK . . . ...... ~. 0 ~ , - ,III- - -.-- -,...., . T - - - - -, - - ~ :':""-'=: , ~ 1- , - - ~ c A ffi t-____ 467-.8DKBLU-::-1 t-____ 461-.8AED .,-.-.-.-~ , .. L.... ..... ,. ......,--- .... • ,• •• I, ---------.- 'F.-----1 -.,_"'' £0_' ..._ _ _ _ 462 8 WHT -. --, ~~ I 120 ~ ~ $ 120-.8GRA i~ ~:o!~ ~ ; • ':J 8153 _ -250-.8 BRN.' _ _ _ _ _ 250-.8 BRN _ , _ _ _ _ _ _ _ 250-.8 BRN • _.~ 440 . .12065401 _ _ _ _ _ _ _ _ _ _ _ 440-.80RN _ _ _ _ _. . . ._ _ _ _ _ _ _ _ 490-.8 RED _ _ _ _ _ _ _ __ ~ ~ FUEL PUMP RELAY ~ ; C-36 i ~ - . . . , . . . , ... 465-.8 OK GRN/WHT .... ,...., . . - , • .... ... ...... ~=~ POWERTRAIN CONTROL MODULE (PCM) OUTPUTS ■ GASOLINE GASOUNE ENGI·NE ENGINE OUTPUTS· ~ 120-.8 GRA F . . . " .......... 450-.8BLK/WHT.-- ,...., ~ . . . . . . . . . Cl03 12052287 -1' ,....-- ~ ..J _ _ ,...., ...... _ , I ~ ..." ,....,,....,,....,...... ...... , &\ G~;r~~D (Q) SHEET - G100 ALTERNATOR BRACKET GROUND G103 ~~~~~ I A e _ ,, -"481-1.0 RED ~250-1.00RN '-439-1.0 PNK/B LKr~""'~~ ~440-1.0 ORN - . . 450-.8 BLKJWHT_ ,..- - -- -- -.- -,.- --,--,-.- -,- -- --..--.- -,-,-,- --,......,- ---_ .. - - - .. --,--I--- . .. - -,-r'" ----..-- - -..... r_- --,...,....--- - - -i:11..- .-..-- .- ~ 450-.8 BLKIWHT r ~ 439-.8 PNK/BLK_ - "-423-.8WHT ~ . . 424-.8 TAN/WHT... "-453-.8 BLK/RED.,. "-430-.8 PPL/WHT_ ,..., ~ -......, 11"- ~ ~,-... j[5Jf 1- ~1228-.8 BLK!RED_ .-... HT _ _ _ _ ..- . . . 454-.8 BLKJW BLK ___ "'487-.8DKBLU "488-.8DKG RN -~--..- ," ......, ~,..-- 7n .,. 1- ~ c:s:::: - -"444-.8DKB LU/BLK' -"442-.8LTB LU/BLK' ""441-.8LTBLU/BLK. GRN . . . 1223-.8 YEllBLK.,. "'490-.8 RED .- ,.. .- " ... r ... ~ r - . - ,. ~ r -"440-1.0 OR N .... -, A c:::J 250 I- ,......- i- -~ _440-1.00RN_ : , j A 2 150 240 111 16 350 B 3 C 140 15 120 o 9 I H 7 E 35 8 F 300 O[ 50 I 1 59 G 39 . 4 5 1 2 (OPENS WHEN BRAKE PEDAL IS DEPRESSED) I -r---. t S207 250-1.0 BRN 10 I J "-419-.8 12015113 SERVICE ENGINE SOON LAMP (SEEPAGE) FUEL CYCLE MODULE (SEEPAGE) ~ 1 G " 0 ~ 35 D 9 ~ 1~0 2 4 5 311~ 300 30 50 8 397 ~ 33 ~ ( 15 120,. 16 350 10 12015964 2 439 1. 420 440 592 593 11 250 419 10 505 481 901 93 75 1824114 4 9 8 6 7 • 1250-1.0 BRNI 3 9 ~~- ~~ II- ~_,,,J .120-.8GRA I- .... - .481-.8 RED i- " -_ ......- -, ;h: - 12085003 (UPPER) 12085002 (LOWER) ..- ..- ,......., ..- ,,~ GT100 I- ..- ,.. -~ ~ -. _430-.8PPL/WHT _ _ ... ... 1229-.8 LT BLU/WHT" 435-.8GRA _ 465-.8 OK GRN/WHT,.. ~1228-.8BLK/RED .-- ... __ ... - • _454-.8 BLKJWHT _ ~ _ 422-.8 TAN/BLK ___ 467-.8 OK BLU 468-.8 OK GRN I- ~443-.8DKB LU/WHT - ~-~-- ..- r..- ~ ~ 1- - 423-.8 WHT _424-.8TAN/WHT _ _ _ _ _ 453-.8BLKlRED _ _ • -- - ~ I- . . 485-.8DKG RN/WHT [g: 44O-.80RN ----- ~ i~ " ......, - . - 439-.8 PNK/BLK _ 120-.8GRA c- II "-435-.8GRA SWITCH 450-.8 BLKJWHT ,...,. ... 450-.8 BLKJWHT ~ _ ~ --- 1..- ,...,- .- -.-... "'1229-.8LTBLU/WHT _ TCC - ~ I- -"120-.8GRA, ~1222-.8LT - ___ I- ~440-.80RN . . . 422-.8 TANI r~ H J K :~I N P 0 W a: 4 35 8 397 — i ~ L _ 33 250pH i 9 — , o 593] 11 140 15 120 1 14201 440 tm m 3 I 16 |350{ i I 4 3 9 1 17 I 2 2 150 ______ i C-40 TRANSMISSION CONTROL MODULE (TCM) DIESEL ENGINE I 250-.8 BRN I I 250-.8 BRN I ENGINE GROUND G109 ~ _ _ _ 439-1.0PNK/BlK _ _ _ .. 250-1.0 OR N ~ ~ _ L ,..,. .... _ - .. -- -- ...-1223-.BYEL/BlK_ _ """439-.B PNK/BlKr .. 1226-.B RED .. 1225-.BDK BlU .. 1224-.B PNK .. 121-.BWHT r- - --- ---1 "L", 439-1.0PNK/BlK _ _ _ . . - - - - - - - - ...,., -,-...,., 1223-.BYEL/BlK ...... ",. . WH._' PNK/BlK~ _ -- ...,., "-476-.B PNK/BlK_~_~'" ~ _ -- - ... ...-42O-.B PPL/B l K _ ..- . . . . _ _ 422-.B TAN/BlK ... ".~----_417-.B DK BLU' . . . . . ...,., ..-1229-.BlT BlU/WHT ....._ _ _ _ _ 440-1.0 OR 476-.8 .... -- ~ 1 - ~ _. '".."'OCUlWH'_ ~ - -., 417-.BOKBLU ~ - -...,., -~-...,.,~=...,., - . .,.,. ........ ...,., - 422-.BTAN/BlK - - ~ .- - -..... -I , ,_ -, B c:J , A 1 ::> c::J qCJ 2 CJ ,--, ':::r-'till3Jill..- •• " , __ - ', -,, ~~ -, .... ... - _~ 4 1225 _~ 5 1226 . CJ6 ~ . " CJ 7 1222 CJ B TsfI. ~ ~~9CJ 11061110 @Bl1 L.... , ,, 1, 112331 11 (12321 12 ...,., ~ ...... ~ ~ CJ 440 lIP l/P CLUSTER (SEE (SEE PAGE 56) 56) 1 T C216 12059125 . .t. . 1 ..I1061-.B ORN/BLK - I, ,~ - ,-r '" -, .- - ~ ~,,. _::J --t ::: :=r. ='--,=....c,. :t:=: :,----. . . . . - _.......... -, ........,...,.............1 ."".,.,"""'"'--,- _.,--.-,......................, I . ~ ~ _1223-.BYEL/BlK_...,., ---------~ ~~ 1 1226-.BRED_. • 1225-.BDKBLU_. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. , 1224-.8 P N K _ I _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _• ~ 1234-.8 GRA/RED 1234-.8GRNRED - ~ 44O-1.00RN N ...- 451-,B WHT/BLK _ ~ _ ..-433-.B GRA/BlKr ~ ...,., ...,., . . - .... 433-.B GRA/BlK ........._ _ _ _.1222-.B IT GRN 1222-.BLTGRN ~.~-----41B-.B GRA GT100 120B5003 (UPPER) 120B5002 (lOWER) ....._ _ _ _ _.452-.B BlK r __ .... ~, 551-1.0TAN/WHT _ _ . . . . . . . . . . . . _ _ "'-1227-.B BLK/YEl_~_ , "'-1231-.B OK BlU/WHT --_ -~ . . . - . _ _ 1230-.BGRNREO_ ~ .. , • ..-122B-.B RE D/BlK,. ~ ~ 1:,~ i ~ ~ iii -- . ~ "450-1.0BlKIWHT--~ ~'" ~ ~ _ ~- 44O-1.00RN ~ r ...,., 2 A 2 150 240 111 439 1 16 350 420 440 592 B 3 C 140 15 120 593 11 0 9 SOB 33 1 j250 E 35 8 397 10 F 300 30 50 901 93 75 1311591 1 1 1 TS24 14 4 G 39 1 3 10 9 8 7 2 4 5 6 0 '" .... ... .. .,-- • ,..,. r ...., ENGINE GROUND G108 G10a ~ . . . ~., ... " . . . C10D H J K M N P - - ...,., - -,-,- ~ - - TRANSMISSION CONTROL MODULE CONNECTORS -,-~--,--- ,- 1231-.BOKBLU/WHT_ _ .'=."'."""- -" ~,,,. - -,-~ _551-1.0TAN/WHT _ _ _ 1227-.BBLK/YEL,. ~ .. , r . . , ~ - - _ . . . . ,. , _ _ ,_ • -" -,~ •• . .---,. . -, 1, - ...." -,-~ -,-.' - -" _ .. - ' - ' - ,-,- - ~~t_'_I :-r; c ~ ~ :~ 0 r , ' - ....... ..., - - __~I_ .. ;--~I- i i i, 'f!:.. -]1 mZJ I ", Lr' ~ - - ~~ "I, __ ':.r===.,-== ~,' !! ! , ~. Iw _ _ ",.. _ _ ...a , , : J ! !Lre, 0 ,ALDL D ~ I _ _ _ _ .~w---------. 1_,...1 ,, 1t----.L---,,_~ _____ J ,~!, .... _ • ~ ~ ~ ...,., ...,., .. 451-.BWHT/BlK _ _ ~ - ...,., ...,., _ . . . , . , ,422-.BTAN/BlK _ ~ _ ~ _ ~ _ _. ~ ~ ~ _ • ....... TRANSMISSION CONTROL MODULE (TCM) ENGINE DIESEL ENGINE C-41 "39-.8 PNK/BLKI ECM-CRNK 10 AMP l/P CLUSTER CONNECTOR 4 39-1.0 PNK/BLK S209 (SEE. PAGE 56) V DRAC MODULE 39-.8 PNK/BLK (Z D i 12261 2 5225] 3 11224 4 □ 4 f 4~6fil (1223) 824-.S LT BLU/BLK - 3JSS21 SPEEDOMETER (SEE PAGE 57) f 4221 5 CZD 6 c m ] ff22§t 7 DPI fi228l 8 HZ] 9 a H a s il 10 [ZD ( p z l 11 [ 435 ] r s n 12 rwi £ z A B C D E F G 2 3 140 9 35 1150 I 240 11111 1439! 17 I [ 16 13501 1 T 14201440 15 120 593 I 68 250 508 33 j w r * 10 505 8 397 [300 30 1 19*1 93 50 1 50 | | [824(14 39 11234 31 1 2 3 4 5 10 9 8 7 — /-\ V —, O X .1 1 591 j 2 592 11 419 -r H l/P J K L .481 W/GASOLINE M 75 4 6 -10 W/DIESEL P 12015964 12015964 12015113 DIESEL ONLY GASOLINE ONLY I GASOLINE ONLY S213 (GASOLINE) (SEE PAGE 30) 39-.S PNK/BLK 1 2 7 10 \ 9 8 6 t 5 G 39|1234 3 1 |^ 5 9 |5 0 | I I \ | 8 2 4 | 14 4 P F I 300 30 P 50 1 93 75 N E 35 8 397-J*-----!---------1 505 D 9 508 33 =T2T68 250 419 140 15 12°!593 11 3 I 16 14201 4401 592 j |B 2 1150 ^ 0 1 1 1 1 1 / 1439 j 17 I 2 3\ * V L, m\ f y -- l 10i \\ M C CRUISE CONTROL MODULE (SEE PAGE 52) SOLINE ONLY 139-.8 PNK/BLK 824-.8 LT BLU/BLK 4 S152 (DIESEL) (SEE PAGE 47) 150-.8 BLKI S112 (SEE PAGES 11, 12) 3Q-.8 PNK/BLK GT100 12085003 12085002 vss 1233-.8 DK GRN/YEL I ■1232-.8 LT BLUI ENGINE (Q ) GROUND G102 C-42 DIGITAL RATIO ADAPTER CONTROLLER (DRAC) DIESEL ONLY ENGINE m q K „ 481 W/GASOLINE 10 W/DIESEL 12015113 CIRCUIT OPERATION WAIT INDICATOR DOES NOT FLASH OR FLASHES FOR THE INCORRECT AMOUNT OF TIME WHEN ENGINE IS BELOW NORMAL OPERATING TEMPERATURE The heating of the Glow Plugs is controlled by the Glow Plug Relay in the Glow Plug Controller. Battery voltage is applied to the relay contacts through the RED (2) wire from Junction Block. The relay is operated by a Solid-State Controller. The Controller responds to engine temperature and also to an Ignition Switch Start Input. When the Ignition Switch is turned to RUN, battery voltage is applied to the Enable Input of the Controller. The Glow Plug Relay within the Controller will be energized for approximately five seconds during which it applies voltage to the Glow Plugs and WAIT Indicator. After the initial time period the relay will be de-energized for five seconds then will cycle ON/OFF for approximately 10 seconds. TEST 1. When the Glow Plug Controller receives the Start Input, the Glow Plugs and WAIT Indicator will cycle ON/OFF after the Ignition Switch is returned to RUN, After approximately 25 seconds the Controller will open the Glow Plug Relay and the heating of the plugs stops. DIAGNOSIS - GLOW PLUGS 2. 3. PRELIMINARY CHECKS: A check of the glow plug system should performed before doing diagnostic procedures. be With engine below normal operating temperature, turn ignition switch to RUN. The WAIT Indicator should light. After approximately 10 seconds, the WAIT Indicator must begin to flash for an additional 10 seconds and then go out. Turn ignition switch to OFF and then momentarily to START and return to RUN position. The WAIT Indicator should flash for approximately 25 seconds and then go out. 4. With engine at normal operating temperature, turn ignition switch to RUN. The WAIT Indicator should flash for a 6.2L engine. 5. ACTION Place ignition switch in RUN position. Connect test lamp from RED (2) wire at glow plug controller connector C190 to ground. Test lamp lights. GO to step 2. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire and fusible link from glow plug controller connector C190 to battery junction block. Connect a test lamp from PNK (3) wire at glow plug controller connector C113 to ground. Test lamp lights. GO to step 3. Test lamp does not light. LOCATE and REPAIR open in PNK (3) wire from glow plug controller connector C113 to fuel shutoff valve connector C129. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from glow plug controller connector C113 to ground G101. Connect a test lamp from PPL (906) wire at glow plug controller connector C113 to ground. Place ignition switch in START position. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in PPL or RST (906) wire from glow plug controller connector C113 to starter motor. Place ignition in OFF position. Connect a test lamp from ORN (503) and ORN/BLK (509) wires at glow plug controller connector C191 to ground. Test lamp lights. REPLACE glow plug controller. Test lamp does not light. GO to step 6. Reading of 2 ohms or less. GO to step 7. Reading greater than 2 ohms. LOCATE and REPAIR open in ORN (503) wire from glow plug controller connector C113 to glow plug harness splice S154. Test lamp cycles on and off for approximately 25 seconds then goes off. GO to step 8. Test lamp does not light or cycles for the incorrect time. REPLACE glow plug controller. Test lamp lights for all glow plugs. LOCATE and REPAIR open in ORN (503) and ORN/BLK (509) wires and fusible links from glow plug to glow plug controller connector C190. Test lamp does not light for one or more glow plugs. REPLACE glow plug(s) where test lamp did not light. Connect a test lamp from PNK (3) wire to BLK (150) wire at glow plug controller connector C113. 6. Disconnect glow plug controller connector C113. Using a positive polarity ohmmeter. Check continuity between ORN (503) and BLK (150) wires. 7. RESULT Connect glow plug controller connector. Connect a test lamp from ORN (503) and ORN/BLK (509) wires at glow plug controller connector C191 to ground. Turn ignition switch momentarily to START and then release to RUN position. 8. Remove all connectors from glow plugs. Connect one lead of test lamp to battery voltage and other lead to each glow plug. GLOW PLUGS C-43 1906-1.0 PPL | ■ 2-8.0 R E D M 1 m f _____ n RIGHT BANK GLOW PLUGS + + LH BATTERY 1906-1.0 PPL I 11-32.0 BLKI RH BATTERY a m 509-5.0 ORN/BLK I 503-5.0 ORN I 503-1.0 ORN I — ■• ■906-.5 R S T B M B (FUSIBLE LINK) E ^O | S150 ■6-5.0 PPL I 503-1.0 ORN I STARTER MOTOR ■2-3.0 R S T » (FUSIBLE LINK) V ■ 6-5.0 PPL I S158 o S101 ■2-2.0 R S T I (FUSIBLE LINK) RH CYLINDER / \ HEAD GROUND O /A O G112 G110 C-44 GLOW PLUGS SHEET METAL GROUND LEFT BANK GLOW PLUGS LH CYLINDER HEAD GROUND 2-5.0 RED I G113 C190 3-5.0 PNK I FUEL SHUTOFF VALVE S GLOW PLUG CONTROLLER 1 2-5.0 RED 4 G H 1C [m L C298 6294641 D C113 12015982 16-5.0 PPL 1509-5.0 ORN/BLK I ■503-5.0 o r n m a m ■ 503-1.0 ORN ■ 13-5.0 PNK I 13-5.0 PNK ■ ■ S200 S105 (SEE PAGE 5) 13-5.0 PNK I 13-5.0 PNK I 1503-1.0 ORN I ■503-1.0 o r n m m m m m 9 12-5.0 RED I 12-5.0 RED I 12-5.0 RED S 250 • 2 1150 I 2 4 0 11111 A 16 3 5 0 1 B 3 C 140 15 120 D 9 508 33 E 35 8 397 ^ F 1 300 30 G 39 (1234 31 | 59 | 50 | I | I 4 3 9 1 17 I 14 2 0 1440 593 68 250 10 505 i9 01| 9 | [ 824} —J ^ -\ L_ w i son r | 4 2 H l/P 592 J 11 K 419 L .481 W /G ASO LINE M 75 n ' ■10 W/D1ESEL 4 P 12015964 S112 (SEE PAGE 1.2) IGNITION SWITCH 12015964 0100 ■6-5.0 PPL I 5-5.0 PPL I 12015113 L r m m r y e l/b lk w DIESEL ONLY G ASO LINE O NLY GASOLINE ONLY GT100 ENGINE 12085003 12085002 j b t I 33 i I 111 481 W /G ASOLINE 3 CO 300 10 W /D IESEL START 12015113 \ RUN O OFF LOCK l/P CLUSTER ° “T __/. (SEE PAGE 56) J B T O ACC ^ H 5 0 5 -.8 YEL/BLK IQ) 1 2-5.0 RED I 1 6-5.0 PPL I = - ENGINE G101 GROUND GLOW PLUGS C-45 FUEL HEATER DOES NOT OPERATE CIRCUIT OPERATION TEST The Diesel Fuel Filter System combines six functions into a single package: 1. It heats diesel fuel to prevent wax-plugging of the filter; 2. It combines very small droplets of water in the fuel into larger drops and separates the water from the fuel; 3. It filters the diesel fuel; 4. It detects an excessive pressure drop indicating filter plugging; (Vacuum Switch) 5. It detects the presence of excess water in the fuel; and 6. It provides a means to drain the water it has separated. thermostatic switch. The switch opens or closes, to turn the heater off or on, depending on the temperature of the fuel. The fuel then passes through the Primary and Secondary filters. Next the fuel flows through the water coalescer. Here the droplets of water in the fuel are combined into larger drops, the drops fall to the water reservoir in the filter. When fuel flows from the Fuel Filter Assembly to the injection pump, it is clean and free of water. A time delay circuit in the Water In Fuel Module grounds the Indicator bulb briefly to test the bulb each time the system is turned on. An electric fuel pump delivers diesel fuel from the tank to the fuel filter. As fuel enters the filter, it passes first through the Fuel Heater. The heater contains a The Fuel Heater is operated by a built-in thermostatic switch. When the switch is closed, battery voltage is applied to the heater from the GAGES Fuse. DIAGNOSIS - DIESEL ENGINE FUEL CONTROLS SERVICE FUEL FILTER INDICATOR DOES NOT LIGHT BRIEFLY WITH IGNITION SWITCH TURNED TO RUN 1. RESULT 2. 3. ACTION Battery voltage. GO to step 2. No voltage reading. CHECK condition of ALT fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire from water in fuel sensor connector C127 to fuse block. Connect a voltmeter from PNK/BLK (39) to BLK (150) wire at water in fuel sensor connector C127. Battery voltage. GO to step 2. No voltage. LOCATE and REPAIR open in BLK (150) wire from water in fuel sensor connector C 127 to ground G102. Connect a voltmeter from YEL/BLK (508) wire at water in fuel sensor connector C127 to ground. Battery voltage. REPLACE water in fuel sensor. No voltage. CHECK water in fuel lamp. If lamp is good, LOCATE and REPAIR open in YEL/BLK (508) wire. Disconnect water in fuel sensor connector C127 and place ignition switch in RUN position. Connect a voltmeter from PNK/BLK (39) wire at water in fuel sensor connector C127 to ground. C-46 FUEL CONTROLS DIESEL ENGINE 2. The Solid-State Water In Fuel Sensor applies voltage to a Probe. When the Probe touches water, the Module closes a switch. This completes a circuit to ground to light the SERVICE FUEL FILTER Indicator. The Fuel Filter Assembly consists of the following main parts: Fuel Heater, the Water In Fuel Sensor, the Fuel Pressure Switch, and a Filter. The Filter contains the coalescer (the device that combines small droplets of water into larger ones) and the filter/separator. TEST 1. RESULT Disconnect fuel heater connector C128. Place ignition switch to RUN position. Connect a voltmeter from PNK/BLK (39) wire at fuel heater connector C128 to ground. Connect a voltmeter from PNK/BLK (39) wire to BLK (150) wire at fuel heater connector C128. ACTION Battery voltage. GO to step 2. No voltage. CHECK condition of ALT fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire from fuel heater connector C128 to fuse block. Battery voltage. REPLACE fuel heater. N o voltage. LOCATE and REPAIR open in BLK (150) wire from fuel heater connector C128 to ground G 102 . WATER IN FUEL INDICATOR LIGHTS WITH NO WATER IN FUEL TEST 1. Place ignition switch in RUN position. Disconnect water in fuel sensor connector C127. RESULT ACTION Water in fuel indicator stays on. LOCATE and REPAIR short to ground in YEL/BLK (508) wire. Water in fuel indicator goes out. REPLACE water in fuel sensor. ■ W V W /W W W V V / < HOT IN STAR T OR RUN ^ >WWVVWVWV'vrA • / Vm S209 (SEE PAGE 42) v ALT 20 AMP FAST IDLE SOLENOID c s 531 COLD ADVANCE CONTROL C *_l m £ S 531 C129 12004267 WATER IN FUEL LAMP (SEE PAGE 56) I 508-.8 YEL I -M r\— I .— ----------------------— ---------------------A A I 439| 17 | 2 H l/P h s q | 2 4 0 I111j P50| | B 3 14201440 I 592 J C 140 » 5 | 20 _ J 593 11 K ^ L_ 250 419 L D 9 S08f33 — , O 10 E 8 [397 ^ Ml w | 19011 93 75 N F 300 30 I 50 | G 39 I |[ 824114 4 P 31 I 59 | 1 2 3 4 5 10 9 8 7 6 J r 6J 311 C100 7 1 2 3 4 5 10 9 6 8 391 31 I 5911111 | 18 2 4 114 4 F I 300 30 I 50 I 1 |901| 93 75 E 35 8 397 _ J _ L _ 10 D 9 508 33 250 419 — . O _ Cj 140 593 11 120 3 \ % |350i. | |4 2 0 | 4401 592 |4 3 9 i 17 | 2 A 2 1150 I 2 4 0 1 I ■ P N M L K J H .................................... ~ V I I 3 UJ > - _____J ENGINE GROUND G102 FUEL SOLENOID FUEL CONTROLS DIESEL ENGINE C-47 AUXILIARY COOLING FAN DOES NOT RUN CIRCUIT OPERATION TEST Battery voltage is applied to the Auxiliary Cooling Fan Relay at all times by the RED (2) wire and by the PNk A/VHT (350) wire through the GAUGES fuse, when the Ignition Switch is in RUN or START. When the Auxiliary Cooling Fan Switch closes at 107°C (225°F), the DK GRN (935) wire is grounded and the Auxiliary Cooling Fan Relay energizes. Battery voltage is applied across the Auxiliary Cooling Fan Motor and the Cooling Fan runs. DIAGNOSIS ~ AUXILIARY COOLING FAN 1. 2. AUXILIARY COOLING FAN RUNS CONTINUOUSLY RESULT TEST 1. 2. ACTION Place ignition switch in RUN position and with engine coolant temperature below 107°C (225°F), disconnect auxiliary cooling fan temperature switch connector C106. Auxiliary cooling fan runs. GO to step 2. Auxiliary cooling fan does not run. REPLACE auxiliary cooling fan temperature switch. Disconnect auxiliary fan relay connector C190. Connect a test lamp from PNK/WHT (350) to DK GRN (935) wires at auxiliary cooling fan relay connector C138. Test lamp lights. Test lamp does not light. CHECK for short in DK GRN (935) wire from auxiliary cooling fan relay connector C138 to auxiliary cooling fan temperature switch connector C106. 3. 4. REPLACE auxiliary cooling fan relay. 5. 6. 7. C-48 AUXILIARY COOLING FAN GASOLINE ENGINE ACTION RESULT Disconnect auxiliary cooling fan temperature switch connector C106. Connect a fused jumper from DK GRN (935) wire at auxiliary cooling fan temperature switch connector C106 to ground. Auxiliary cooling fan does not run. GO to step 2. Auxiliary cooling fan runs. REPLACE auxiliary cooling fan temperature switch. Disconnect auxiliary cooling fan relay connector C138. Connect a test lamp from PNK/WHT (350) wire at auxiliary cooling fan relay connector C138 to ground. Test lamp lights. GO to step 3. Test lamp does not light. CHECK condition of GAUGES fuse and/or LOCATE and REPAIR open in PNK/WHT (350) wire from auxiliary cooling fan relay to fuse block. Connect fused jumper from DK GRN (935) wire at auxiliary cooling fan temperature switch connector C106 to ground. Connect a test lamp from PNK/WHT (350) wire to DK GRN (935) at auxiliary cooling fan relay connector C138. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in DK GRN (935) wire between auxiliary cooling fan temperature switch connector C106 and auxiliary cooling fan relay connector C138. Connect a test lamp from RED (2) wire at auxiliary cooling fan relay connector C138 to ground. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in RED (2) wire and fusible link between auxiliary cooling fan relay connector C138 and battery junction block. Connect 30 amp fused jumper from RED (2) wire to BLK/RED (702) wire at the auxiliary cooling fan relay connector C138. Auxiliary cooling fan does not run. GO to step 6. Auxiliary cooling fan runs. REPLACE auxiliary cooling fan relay. Leave 30 amp fused jumper connected. Disconnect auxiliary cooling fan connector C152. Connect a test lamp from BLK/RED (702) at auxiliary cooling fan connector C 152 to ground. Test lamp lights. GO to step 7. Test lamp does not light. LOCATE and REPAIR open in BLK/RED (702) wires from auxiliary cooling fan connector C152 to auxiliary cooling fan relay connector C138. Connect a test lamp from BLK/RED (702) to BLK (150) wires at auxiliary cooling fan connector C152. Test lamp lights. REPLACE auxiliary cooling fan. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from auxiliary cooling fan to ground G102. GAGES 20 AMP a S218 I 350-.8 PNK/WHT I (GASOLINE ONLY) (SEE PAGE 38) BATTERY JUNCTION BLOCK o o o o ? y I 2-.8 RST ■ ■ ■ S104 p (FUSIBLE LINK) « r\ 150 -r — 150-.8 BLK I 2-2.0 RED i I 4 3 9 1 17 I 2 592 593 11 L _ 68 250 419 r— 10 505 n I 1901] 93 75 | 824| 14 4 10 9 8 7 6 U — 3 *■ o' CM 2 |1 5 0 » 4 0 | 1 1 l | A B 3 I 16 13 5 0 1 | C 140 15 120 _ J ^ D 9 508 33 — n O 8 397 ^ E 35 w F !3 0 0 I 30 I 50 G 39 11234! 31 | 59 | 50 | 1 2 3 4 5 H J K l/P L .481 W /G ASOLINE M N ■10 W /DIESEL P 12015964 k- I 2-2.0 RED C100 702-2.0 BLK/RED DIESEL ONLY G ASO LINE ONLY | ^GASOLINE ONLY 702 ENGINE I 9 3 5 ,8 DK GRN AUXILIARY COOLING FAN 481 W /G ASOLINE r 10 W /D IESEL 12015113 150 ’/> ~) 12085003 (UPPER) 12085002 (LOWER) 150-.8 BLK 9 3 5 ,8 DK GRN I AUXILIARY COOLING FAN PRESSURE SWITCH GT 100 • S 114 C153 12015792 I 150-.8 BLK I I 935-.8 DK GRN 935-.8 DK GRN I I 150-.8 BLK ; • | S112 (SEE PAGE 11) I v ' 702-2.0 BLK/RED I 2-2.0 RED AUXILIARY COOLING FAN TEMPERATURE SWITCH (CLOSED WHEN COOLANT EXCEEDS 225°F) ENGINE GROUND COOLING FAN RELAY AUXILIARY COOLING FAN GASOLINE ENGINE C-49 PROVISIONS FOR AIR — — — o m jo kg rn , CONDITIONING B A r- 1*40 I 1 I.463J f ia o l z l« * l A 2 1150 I 24C B 3 I 16 |350| C 140 15 120 D 9 508 33 E 35 8 397 F 1300 30 G 39 11234 31 I 1 2 3 S3 C 14391 17 I 2 142014 4 0 1592 “T t 593 11 J /~ \ L_ 68 250 419 O r 10 505 1 ^ n 50 \ •I » l X 5 !901| 93 i f j 10 9 |824| 14 8 7 H l/P J K L .481 W/GASOUNE M 75 N' 4 6 P -10 W/DIESEL 12015113 DIESEL ONLY GASOUNE ONLY I GASOUNE ONLY 481 W/GASOUNE 10 W/DIESEL S123 zC C sO 0 Q m 59-.8DKGRN| 150-.8 BLK I • S112 (SEE PAGE 11) COMPRESSOR sue 159- 8 DK GRN 59-.8 DK GRN ENGINE GROUND G102 C-50 PROVISIONS FOR AIR CONDITIONING GASOLINE ENGINE GT100 12085003 (UPPER) 12085002 (LOWER) C Z 3 4 I435I rVsTl a C Z I 6 I439] c E POWERTRAIN CONTROL MODULE D bb ] 7 t ia a l I'ss '] B L.4B1] C Z ] 9 UsTI I 434 I 10 GUI r~ ]u m i C251 12052175 C100 IN-UNE DIODE C3 CO \ 4B0I 12015964 S124 3 L CIRCUIT OPERATION TEST The Cruise Control regulates the speed of the vehicle in response to driver commands. The Cruise Control Module contains electronic circuitry and a stepper motor. The other system components are: • • • Cruise Control Switch Brake Switch Vehicle Speed Sensor (VSS) The Cruise Control Module receives voltage from the IGN Fuse in RUN or START. A speed signal is received from the VSS. The driver gives his input to the Cruise Control Module through the components listed above. The Cruise Control Module circuitry receives the driver’s input and generates electrical pulses. These pulses cause the stepper motor and its output reel to rotate. The throttle is controlled by a cable wound on the output reel. The Cruise Control Module also contains a clutch which releases the cable when the Cruise Control System must be shut off. This clutch will operate when the Brake Pedal is depressed, the Cruise Control System is turned off, or the Cruise Control System detects a failure. RESULT Test lamp lights. GO to step 6. Test lamp does not light. LOCATE and REPAIR open in GRA (397) wire from brake switch connector C245 to splice S215. Test lamp lights. GO to step 7. Test lamp does not light. LOCATE and REPAIR open in TAN (901) wire from brake switch connector C246 to cruise control module connector C248. Test lamp lights. GO to step 8. Test lamp does not light. CHECK adjustment of brake switch. If properly adjusted, REPLACE brake switch. Test lamp lights. GO to step 9. connector C245 to ground. Test lamp does not light. CHECK adjustment of brake switch. If properly adjusted, REPLACE brake switch. Connect a test lamp from DK BLU (84) wire at cruise control switch connector C244 to ground. Test lamp lights. REPLACE cruise control switch. Test lamp does not light. GO to step 10. Test lamp lights. GO to step 11. Test lamp does not light. REPLACE cruise control switch. Test lamp lights. GO to step 12. Test lamp does not light. LOCATE and REPAIR open in DK BLU (84) wire from cruise control module connector C248 to cruise control switch connector C244. 12. Depress and hold RESUME/ ACCEL switch. Connect test lamp from DK GRN (83) wire at cruise control switch connector C248 to ground. Test lamp lights. GO to step 13. Test lamp does not light. REPLACE cruise control switch. 13. Connect a test lamp from DK GRN (83) wire at cruise control module connector C248 to ground. Test lamp lights. GO to step 14. Test lamp does not light. LOCATE and REPAIR open in DK GRN (83) wire from cruise control module connector C248 to cruise control switch connector C244. 14. Raise vehicle so drive wheels can be turned by hand. Connect voltmeter from PNK/WHT (39) wire to DK GRN (389) wire at cruise control module connector C248. Slowly turn drive wheels. Pulses between 0 and battery voltage as wheels are turned. REPLACE cruise control module. Does not pulse or no voltage reading. CHECK speed sensor circuit. Refer to Fuel, Driveability and Emission Manual (Gasoline). 5. Connect a test lamp from GRA (397) wire at brake switch connector C245 to ground. 6. Connect a test lamp from TAN (901) wire at brake switch connector C246 to ground. 7. Connect a test lamp from BRN (86) wire at brake switch connector C246 to ground. DIAGNOSIS - CRUISE CONTROL CRUISE CONTROL DOES NOT DISENGAGE WHEN BRAKE PEDAL IS DEPRESSED 1. ACTION RESULT TEST Place ignition switch in RUN position and cruise control switch to ON. Depress brake pedal. Connect test lamp from BRN (86) wire at brake switch connectors C245 and C246 to ground. Test lamp does not light. REPLACE control module. Test lamp lights. CHECK adjustment of brake switch. If adjustment cannot be corrected, REPLACE brake switch. 8. Connect a test lamp from BRN (86) wire at brake switch 9. 10 . Depress SET switch. Connect a CRU ISE CONTROL DOES NOT OPERATE TEST RESULT ACTION Place ignition switch in RUN and cruise control switch to ON. Connect a test lamp from PNK/BLK (39) wire at cruise control switch connector C244 to ground and then cruise control module connector C248 to ground. Test lamp lights. GO to step 2. Test lamp does not light. CHECK condition of IGN fuse. If fuse is good, LOCATE and REPAIR open in PNK/BLK (39) wire from cruise control switch connector C244 and cruise module connector C248 to fuse block. Connect a test lamp from GRA (397) wire at cruise control switch connector C244 to ground. Test lamp light. GO to step 3. Test lamp does not light. REPLACE cruise control switch. 3. Connect a test lamp from GRA (397) at cruise control module connector C248 to ground. Test lamp lights. GO to step 4. Test lamp does not light. LOCATE and REPAIR open in GRA (397) wire from cruise control module connector C248 to cruise control switch connector C244. 4. Test lamp lights. GO to step 5. Test lamp does not light. LOCATE and REPAIR open in BLK (150) wire from cruise control module connector C248 to ground G202. 1. 2. Connect a test lamp from GRA (397) to BLK (150) wires at cruise control module connector C248. ACTION test lamp from DK BLU (84) wire at cruise control switch connector C244 to ground. 1 1 . Connect a test lamp from DK BLU (84) wire at cruise control module connector C248 to ground. CRUISE CONTROL C-51 yW W vW W vW V / s HOT IN START OR RUN Z >VVV\M/VVVWW''* ALT 20 AMP IGNITION * - 39 ACCEL/RESERVE SW CRUISE ENGLARGER SWITCH GROUND - 83 - 84 - 150 VEHICLE SPEED INPUT ELECTRONIC CRUISE - 389 - 397 _ 901 BRAKE SWITCH CRUISE CONTROL MODULE 8209 09 (SEE PAGE 42) $ B 2' 4011111 A 161 l/P >l 17 I >01440 { 592 l/P 68 250 419 .481 W/GASOLINE C D E F g 397 1300 551 O 10 505 1901J 9 3 31159 ( 50 | 1 | l824jT4 10 9 8 10 W/DIESEL C100 12015113 DIESEL ONLY GASOUNE ONLY GASOLINE ONLY ENGINE I 150-.8 BLK I S112 (SEE PAGES 11, 12) 481 W/GASOLINE 10 W/DIESEL GASOLINE ONLY DIESEL ONLY GT 100 12085003 (UPPER) 12085002 (LOWER) BRAKE SWITCHES (OPEN WHEN BRAKE PEDAL IS DEPRESSED) § d > co o co m * 0 i $ * I 3S9-.8 DK GRN I Z DRAC (SEE PAGE 42) CRUISE CONTROL ACTIVATOR C245 12010649 ' 39-.8 PNK/BLK I 139-.8 PNK/BLK S213 (SEE PAGE 30) I 397-.8 G R A B * ■397-.8 G R A ^ H S215 1 901 -.5 TAN ■ ■ A ENGINE (Q ) GROUND G102 C-52 CRUISE CONTROL DIAGNOSIS - INSTRUMENT PANEL: GAGES AND INDICATORS CIRCUIT OPERATION The operation of an individual Indicator is described along with its circuit. Refer to the schematic and text for the circuit that is indicated below each of the Indicators. PARK BRAKE WARNING LAMP Battery voltage is applied to the Brake Indicator when the Ignition Switch is in RUN, or START. Three Switches are connected to the Brake Indicator. When any one of these switches closes, a ground is provided and the indicator lights. The Park Brake Switch provides a ground when the Park Brake is applied. The Brake Indicator lights to alert the driver. The Brake Pressure Switch closes to light the Brake Indicator when there is low brake fluid pressure in one of the two hydraulic brake systems. This could be caused by a leak in one of the brake lines. The Ignition Switch grounds the Brake Indicator when the Ignition Switch is turned to START to provide a quick check of the Brake Indicator Bulb and circuitry. FUEL GAGE The pointer of the Fuel Gage is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the E-coil and the circuit divides at the opposite end of the coil. One path continues to ground through the F-coil. Another goes to ground through the variable resistor of the Fuel Gage Sender. When the tank is low, the resistance of the Sender is low. A large flow of current passes through the E-coil and the Fuel Gage Sender resistor. This moves the pointer toward E on the scale. When the tank is full, the Sender resistance is high. More current now flows through the F-coil, moving the pointer toward F on the scale. With two coils operating the pointer, the Gage is not affected by changes in the system’s battery voltage. TEMPERATURE GAGE PRELIMINARY CHECKS: The Temperature Gage is also operated by two coils. Battery voltage is applied to both coils. One is grounded directly and the other is grounded through the Temperature Sender. This has 55 ohms resistance at 127°C (260°F) (hot coolant) and its resistance becomes greater at lower temperatures. It is approximately 1400 ohms at 38°C (100°F). This causes the current through the Sender and one coil to increase as the coolant temperature increases. This moves the pointer. Check the condition of GAGES and INST LPS fuses. If fuses are in good condition, use the following diagnostic procedures. FUEL GAGE INDICATES FULL OR BEYOND AT ALL TIMES TEST 1. LOW COOLANT INDICATOR (DIESEL) The Low Coolant Indicator comes on to warn the driver when a low level of coolant exists in the radiator. Battery voltage is applied to the Low Coolant Module. When a low coolant condition exists, a signal is sent to the Low Coolant Module from the Low Coolant Sensor. The Low Coolant Module will provide a ground to the Low Coolant Indicator. The Low Coolant Sensor is not a switch that opens and closes. It has a very high resistance to ground, more than 50,000 ohms, when the engine coolant level is low. This causes the Low Coolant Module to light the Low Coolant Indicator. With more of the Sensor covered by coolant, its resistance decreases. When the fluid level is good, the resistance between 10,000 and 50,000 ohms, the Sensor is partly covered and the fluid is not low enough to cause the warning to be displayed. CHECK ENGINE (GASOLINE) INDICATOR 2. RESULT ACTION Disconnect fuel pump connector C401 and place ignition switch to RUN. Connect a fused jumper from PNK (30) wire at fuel pump connector C401 to ground. Fuel gage indicates full. LOCATE and REPAIR a short in PNK (30) wire. If not short is found, REPLACE fuel gage. Fuel gage indicates empty. GO to step 2. Connect a fused jumper from PNK (30) wire to BLK (150) wire at fuel pump connector C401. Fuel gage indicates full. LOCATE and REPAIR open in BLK (150) wire. Fuel gage indicates empty. REPAIR/REPLACE fuel pump. FUEL GAGE INDICATES EMPTY WHEN THERE IS FUEL IN THE TANK TEST 1. Disconnect fuel pump connector C401 and place ignition switch to RUN. RESULT ACTION REPAIR/REPLACE fuel pump. Fuel gage indicates full. LOCATE and REPAIR a short in PNK (30) wire. If no short is found, , REPLACE fuel gage. Fuel gage indicates empty. FUEL GAGE IS INACCURATE TEST 1. Refer to Light Duty Truck Fuel, Driveability and Emissions Service Manual, Section 3. WATER IN FUEL WARNING INDICATOR Refer to Fuel Controls (Diesel), Page B-38. GLOW PLUG INDICATOR Disconnect fuel pump connector C401. Connect one RED lead of J 34029-A Multimeter to PNK (30) wire and other to ground. Set resistance dials to 0 ohms and then to 90 ohms. Fuel gage should indicate empty and then full. (Allow time for gage to reach full due to anti-slosh device.) RESULT ACTION Gage responds correctly. CHECK BLK (150) wire for high resistance. If wire is good, REPAIR/REPLACE fuel pump. Gage does not respond correctly. CHECK for high resistance in PNK (30) wire. If wire is good, REPLACE fuel gage. Refer to Glow Plugs (Diesel), Page B-11. OIL PRESSURE GAGE INDICATES LOW PRESSURE WHEN OIL PRESSURE IS GOOD RH/LH TURN SIGNAL INDICATORS TEST Refer to Front Exterior Lamps, Page B-24. 1. OIL PRESSURE GAGE HIGH BEAM INDICATOR The engine oil pressure is displayed by the Oil Pressure Gage. The pointer of the Gage is moved by two coils, and its operation is similar to that of the Fuel Gage. DRL INDICATOR Refer to Headlamps, Page Refer to Headlamps with Canadian Daytime Running Lamps, Page Disconnect oil pressure sender connector C118 (Gasoline) or C119 (Diesel) and place ignition switch to RUN. RESULT ACTION Oil pressure gage indicates high pressure or indicator light goes out. REPLACE oil pressure sender. Oil pressure gage indicates no or low pressure or indicator light stays on. LOCATE and REPAIR short in TAN (31) wire. If wire is good, REPLACE oil pressure gage. The Oil Pressure Sender is connected to the junction of the two coils. It has low resistance when the oil pressure is low, and 90 ohms resistance when the oil pressure is high. This changing resistance changes the current flow through the coils. The magnetic field of the coils move the pointer from low to high. INSTRUMENT PANEL C-53 OIL PRESSURE GAGE INDICATES HIGH PRESSURE AT ALL TIMES TEST RESULT 1. Disconnect oil pressure sender connector C118 (Gasoline) or C119 (Diesel) and place ignition switch to RUN. Connect a fused jumper from TAN (31) wire at oil pressure sender connector C118 (Gasoline) or C119 (Diesel) to ground. ACTION Oil pressure gage indicates low pressure or indicator lights. REPLACE oil pressure sender. Oil pressure indicates high pressure or indicator does not light. LOCATE and REPAIR open in TAN (31) wire. If wire bulb is good, REPLACE oil pressure gage. TEMPERATURE GAGE INDICATES HOT WITH ENGINE COOLANT BELOW OPERATING TEMPERATURE AND IGNITION SWITCH IN RUN RESULT TEST 1. Disconnect temperature sender connector C104 (Gasoline) or C108 (Diesel) and place ignition switch to RUN. ACTION Temperature gage indicates cold. REPLACE temperature sender. Temperature gage does not indicate cold. LOCATE and REPAIR a short in DK GRN (35) wire. If no short is found, PERFORM diagnostic procedures under symptom MTemperature Gage Is Not Accurate.- TEMPERATURE GAGE INDICATES COLD ALL THE TIME ACTION RESULT TEST 1. Disconnect temperature sender connector C104 (Gasoline) or C108 (Diesel). Ground the DK GRN (35) wire at temperature sender connector C1 04 (Gasoline) or C108 (Diesel). Temperature gage indicates hot. REPAIR/REPLACE temperature sender. Temperature gage does not indicate hot. LOCATE and REPAIR open in DK GRN (35) wire. If wire is good, REPLACE temperature gage. TEMPERATURE GAGE IS NOT ACCURATE TEST 1. Disconnect temperature sender connector C104 (Gasoline) or C108 (Diesel). Connect RED lead from J 34029-A Multimeter to DK GRN (35) wire and other lead to ground. Adjust resistance dials to 1400 ohms and then to 55 ohms. Temperature gage should indicate cold then hot. RESULT ACTION Gage indicates correctly. REPLACE temperature sender. Gage is not correct. LOCATE and REPAIR open in DK GRN (35) wire. If wire is good, REPLACE temperature gage. LOW COOLANT INDICATOR IS LIT WHEN COOLANT LEVEL IS GOOD TEST 1. Connect a fused jumper from low coolant warning switch connector C150 to ground. Place ignition switch to RUN and observe low coolant indicator light. C-S4 INSTRUMENT PANEL RESULT ACTION Low coolant indicator goes out. REPLACE low coolant probe. Low coolant indicator stays lit. LOCATE and REPAIR open in YEl/BLK (68) wire. If wire is good, follow diagnostic procedures listed under symptom -Low Coolant Indicator Does Not Light With Coolant Level Low.· LoWCO oLANT INDICTOR DOES NOT LIGHT WITH COOLANT LEVEL LOW (DIESEL ONLy) TEST 1. Disconnect low coolant warning switch connector C 126 and place ignition switch to RUN. Observe low coolant indicator light. RESULT ACTION Low coolant indicator lights. REPLACE low coolant warning switch. Low coolant indicator does not light. GO to step 2. 2. Disconnect low coolant warning module connector C223. Connect voltmeter from BLKlORN (550) wire at low coolant warning module connector C223 to ground. Battery voltage. GO to step 3. No voltage. LOCATE and REPAIR open in BLU/ORN (550) wire. If wire is good, REPLACE GAUGES fuse. 3. Con nect a voltmeter from PNKlBLK (39) wire to BLK (150) wire at low coolant warning module connector C223. Battery voltage. GO to step 4. No voltage. LOCATE and REPAIR open in BLK (150) wire. 4. Connect a voltmeter from GRA (69) wire at low coolant warning module connector C223 to ground. Battery voltage. GO to step 5. No voltage. LOCATE and REPAIR short to ground in GRA (69) wire from low coolant warning module connector C223 to low coolant warning lamp. 5. Connect a voltmeter from PNKlBLK (39) wire to YEl/BLK (68) at low coolant warning module connector C223. Battery voltage. LOCATE and REPAIR short to ground in YEl/BLK (68) wire from low coolant warning module connector C223 to low coolant warning switch connector C126. No voltage. REPLACE low coolant module. ILLUM ILLUM ILLUM -- ILLUM ILLUM ILLUM : v r------r---, I LEFT HIGH BEAM TURN Q ~5~Q) '150 _ RIGHT TURN _1~ - 15 -,- : I ORL I (C~~~~,AQ N ~ bi 150 I r--- : '- I I 593: I L ________ 11 ...J (629W/DRL) 39 r-- - 419 WATER IN FUEL (DIESEL ONLy) LOW COOLANT .... SERVICE ENGINE SOON PARKING BRAKE SERVICE BRAKE - GLOW PLUG (DIESEL ONLy) - SPEEDOMETER FUEL VOLT r ~ ,,.. = = e~ -e F • = eg.. eM "'e L-~~------------~~----------------~----------------~----------~--+-+-t--39----~==~&.~ M ..~te~ --~----~ - ~ .= · == ------- I ~ ~ C218 12040746 ~---- 68----..... ~ 507-----+--~~ e~ "'0 _____+--J ., AetlF=tfI-419 ---~~-----+~~+-' e~ 111 :==:a:==~=+:t' e~ '" ~ 33 824 ---4III-III-;ffioe'" ... ~tF~HI--l50 _-+----~- 39 ---------------t----------------""""I~-------------+----_I~_+--1_-150 - I --- 8 ~ C1i - O~ ~e ' - - - - - 3 5 -~"-=HI"~ ~. r - - 31 _~~---150 1""'"1234 t:i :!e - TEMP 1 ~. ~ ...~ ,---.""'-~ - OIL 0 :::== • 593----~~-----+~ .. !== • F= • ~etlF=HI'-l50 -----+-----.. A~ ~~f.p;;;~1-P-15----_+----"" --------------""""I~--------------~------_I--_+--~--+_11~29--~t:~~~~~~~~~::J1~14----~~ ----" ........... I ~ '" / l\.T}JI. INSTRUMENT PANEL C-55 RPO RPO CODES CODES C7P C7P -- 16,000 16,000 lBS LBS GWI GVW RATING RATING ALT 20 AMP GAUGES 20 AMP ~ ~ '-- - 550-.8 BLK/ORN _ ~ -"..,,,"'"'- -- - -------- ---- ---~ ." 15 ~ .-r _ _ .-r ~ ,..,. Z ::::j ..-r -< 02l Cl 2l 0 c: » ;: UI ." ::::j r 0 Z 0 0 z ;: LOW COOLANT WARNING MODULE ::E (') :r 150 550· LOW COOLANT WARNING SENSOR (DIESEL ONLy) 69 68 A AUTO APPLY PARK BRAKE SWITCH C223 12004706 (DIESEL ONLy) ONLY) (DIESEL C126 . - 550-.8 BlK/ORN _ ...... . - r _ --- , ~ "A o ~ _ ~ ~ ..-r _ 0 9 508133l E 35 8 397 F 300 30 50 G 391 12341311591501 1 1 2 3 4 5 10 -- r 439 17 4:!11 440 593 68 250 10 505 901 93 824'14 9 8 7 ~ ~ 508-.8YELJBlK"'..-r _ _ IS APPLIED) 33 450 2 592 11 419 75 4 6 H I/P ...,.. _ 33-.8 TAN/WHT _ J K l MI N P (CLOSED (CLOSED WHEN WHEN PARKING PARKING BRAKE BRAKE IS IS APPLIED) APPLIED) ~ C220 12010651 IGNITION SWITCH (SEE PAGE 4) _33-.5TAN/WHT..,. . . . . 481 W/GASOlINE . . . . . -1..-450-.8BlKIWHT . . - 10 W/DIESEl ~ ...J III 12015964 0 419 593 11 K 14201440)592 J I 439 j 17 I 2 H 8 I \|8 2 4 | I 19011 I 1 10 —— L T l ENGINE „ 481 W/GASOUNE '1 0 W/DIESEL DIESEL ONLY - P 19 18 I M 16 L 27 K 15 J he 14 H 28 G f I [ I S-.5 GRA I F E D 12004147 PRNDLLAMP Q 12004148 C211 - 8-.5 GRA - TURN SIGNAL SWITCH C-58 INSTRUMENT PANEL LAMPS l/P GROUND G200 HORN/OM ~_ _ _ _ _ _ _ _ _ _ _ 240-1.00RN _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. . 15 AMP '1 A 2 150 240 111 16 350 B 3 C 140 15 120 0950833 E358397 F 300 30 50 G 39 1234 31 59 50 1 2 3 4 5 439 17 2 420 440 592 593 11 68 250419 10 505 901 93 75 o 10 9 824 14 8 7 : H J liP K L 481 W/GASOLINE N 10 W/OIESEL P 12015964 M( 44 C100 PANEL DIMMER SWITCH C202 12020029 156 150 DOME 2 C203 12020030 CIRCUIT BREAKER 25 AMP "PARK I I HEAD LIGHT SWITCH 40 15B-.8WHT ............................. (SEE PAGE 18) 'PARK 9 LIGHT SWITCH .-_150-3.0 BLK _ _ _" S214 , HEAD S206 10 OFF 1"__ 24O-1.00RN _ _ _~ ~ ~ . . . .- - - - - - - -. .- - -. .- - - - - - - - - - - -. .- - - - - - - - - - - - - - - - - -. . PROVISIONS FOR DOME LAMPS 2~5981 HORN RELAY (SEE PAGE 26) liP l/P GROUND G200 A ~ - PROVISIONS FOR DOME LAMPS C-59 CIRCUIT OPERATION BACKUP LAMPS DO NOT OPERATE TEST BACKUP LAMPS PARK, TAIL, MARKER, AND LICENSE LAMPS With the Ignition Switch in RUN or START, voltage is applied through the TURN/BU Fuse to the Transmission Position Switch or the Backup Lamp Switch. Whenever the gear selector lever is shifted to REVERSE, the Transmission Position Switch or the Backup Lamp Switch closes and voltage is applied to the Backup Lamps and the lamps turn on. Voltage is applied through the TAIL LPS Fuse to the Light Switch at all times. With the Light Switch in PARK or HEAD, voltage is applied to the Park, Tail, Marker, and License Lamps. 1. 2. Place transmission in reverse. Connect test lamp from LT GRN (24) wire at rear lamp harness connector C400 to ground. RESULT Test lamp lights. ISOLATE problem in body builder’s installed wiring. Test lamp does not light. GO to step 2 . Connect a test lamp from DK BLU (75) wire at backup lamp switch connector C214 to ground. Test lamp lights. GO to step 3. Test lamp does not light. CHECK condition of TURN/BU fuse. If fuse is good, LOCATE and REPAIR open in DK BLU (75) wire from backup lamp switch connector C214 to fuse block and DK BLU (38) wire. Connect a test lamp from LT GRN (24) wire at backup lamp switch connector C214 to ground. Test lamp lights. LOCATE and REPAIR open in LT GRN (24) wire from backup lamp switch connector C214 to rear lamp harness connector C400. Test lamp does not light. Adjust backup lamp switch. If backup lamp switch will not adjust properly, REPLACE backup lamp switch. DIAGNOSIS - REAR EXTERIOR LAMPS PRELIMINARY CHECKS: The rear lamp systems (taillamps, backup lamps, and license plate lamps) all receive voltage from the same wire circuit (BRN 9) and are grounded at the bulb socket(s). If only one system is not working, LOCATE and REPAIR an open in the wiring and/or bulbs that pertain to that system. NONE OF THE REAR LAMP SYSTEMS OPERATE TEST 1. 2. 3. RESULT ACTION Connect a test lamp from ORN (40) wire at light switch connector C202 to ground. Test lamp lights. GO to step 2. Test lamp does not light. CHECK condition of TAIL LPS fuse. If fuse is good, LOCATE and REPAIR open in RED (2) wire from light switch connector C202 to battery junction block and/or ORN (40) wire from light switch connector C202 to fuse block. Place light switch to PARK position. Connect test lamp from BRN (9) wire at light switch connector C202 to ground. Test lamp lights. GO to step 3. Test lamp does not light. REPLACE light switch. Test lamp lights. LOCATE and REPAIR open in BLK (150) wire. Test lamp does not light. LOCATE and REPAIR open in BRN (9) wire from rear lamp harness connector C400 to light switch connector C202. Connect a test lamp from BRN (9) wire at rear lamp harness connector C400 to ground. C-60 REAR LAMPS 3. ACTION 24-.8 LT GRN ■ RH BACKUP LAMP PROVISIONS FOR RH SIDE MARKER [CUD] (CHDh-8BLK C406 2977107 RH TAIL STOP AND TURN LAMP 07 I RH LICENSE LAMP NOTE: THIS HARNESS IS SHIPPED ALONG WITH THE VEHICLE AND INSTALLED BY THE BODY BUILDER. LH LICENSE LAMP LH BACKUP LAMP LH TAIL, STOP AND TURN LAMP ^ 2 4 ^ - 6BLK^ C405 2977107 PROVISIONS FOR LH SIDE MARKER 24-,8 LT GRN REAR LAMPS HARNESS C-61 C247 12020030 PANEL DIMMER SWITCH 156 C202 12020029 9 HEAD LIGHT SWITCH I 9-1.0 BRN _J LZ o ^ ^ r~ I 59! I I -------------- -----DIESEL ONLY CM 39 1 -■ [ 439 17 | 14201440 593 250 10 | 19011 93 14 10 9 8 7 r\ i | | 2 592 11 419 * 75 4 6 9-.8 BRN 1 9 35 i 1150 | 2 4 0 11111 I 16 1350J | 15 120 33 ^ 8 397 !300 30 I 50 I I 31 2 3 4 5 CO p A B C D E F G H l/P J K L .481 W/GASOLINE M N* •10 W/DIESEL P 12015964 C100 GT100 C-62 TAILLAMPS S115 (SEE PAGE 15) 12085003 (UPPER) 12085002 (LOWER) C400 12065150 I ID 0] TRANSMISSION BACKUP LAMP SWITCH I I 1 !I J] [][][ I □ VAM M M /W VW V* < HOT IN START OR RUN ? m w /w w v w ^ II □ 11 I ■H I B/f I II □ I H IkS Ekfi 4-0 (pi 0yfl Ik® Skf I [ kS A —S [«k1 I [ k S fri I o) REAR LAMP HARNESS I 24-1.0 LTGRN1 A B C D E F G 2 150 | 240 J1111 | 3 I 16 13501 | i 140 15 120 — I ^ -\ 9 508 33 — « 35 8 397 ^ ^ |300 30 i 50 | I 39 11234 311 59 | 50 | | 1 2 3 4 5 10 -j— v -r— o I 4391 17 1 , 2 I420l44tf L592 59: I 11 I— 68 250 B19 ^ 10 5 0 5 1 ,3 n 1901] 93 75 J824I 14 4 9 8 7 6 -r H l/P J K L -481 W/GASOLINE M [-10 W/DIESEL P 12020926 I 7S-.BOKBLU C100 BACKUP LAMPS C-63 CIRCUIT OPERATION EGR VALVE VACUUM SYSTEM VACUUM SYSTEMS A vacuum-operated component uses the force of normal air pressure working against the lower air pressure of a partial vacuum to operate the component. The vacuum created within the inlet manifold when the engine is running is stored in a vacuum tank in the engine compartment. A check valve in the line feeding vacuum to the tank keeps the stored vacuum from weakening when inlet manifold vacuum drops during high speed or high power operation. Vacuum is routed through hoses (and in some cases, tubing) to a mechanical or electric valve that provides a means of controlling the vacuum-operated component. When the valve is open, it allows vacuum to go to an actuator that actually operates the component. When the component is to be returned to its original position, the valve cuts off the vacuum to the actuator hose and vents the hose to normal air pressure. A typical actuator is a metal shell with a movable shaft that retracts and extends to mechanically operate the component. A flexible diaphragm separates the interior of the shell into two chambers - a sealed chamber to which vacuum can be admitted, and an open chamber exposed to normal air pressure. The movable shaft is attached to the center of the diaphragm and extends from the open chamber. When the vacuum is directed to the sealed chamber, normal air pressure presses on the other side of the diaphragm and causes it to retract the shaft. When the vacuum is cut off, the sealed chamber is vented to outside air to balance the air pressure on both sides of the diaphragm and eliminate the force that retracted the shaft. A coiled spring within the sealed chamber expands to push the diaphragm back to its original positions. This extends the shaft. EXHAUST GAS RECIRCULATION VACUUM SYSTEM All 1991 P-Motorhome gasoline engines are equipped with an exhaust gas recirculation (EGR) system. The EGR system allows a small amount of exhaust gas to flow from the exhaust manifold into the inlet manifold when the throttle is opened beyond idle and inlet manifold vacuum is normal. This reduces combustion temperatures in the engine to control oxides of nitrogen emissions. C-64 VACUUM SYSTEM The EGR valve is operated by an integral vacuum actuator that controls a pintle within the valve. The pintle remains closed to prevent exhaust gas recirculation until vacuum is applied to the actuator. The vacuum causes the pintle to open, allowing a measured flow of exhaust gas to enter the inlet manifold. The EGR system remains closed during periods of engine idle and deceleration to prevent rough idle from excessive dilution of the fuel-air mixture. It also remains closed at wide-open throttle to prevent power loss. At other times, it rapidly cycles open and closed to modulate the flow of exhaust gas as required. Under certain circumstances, it may remain fully open to provide the maximum EGR. A manifold absolute pressure (MAP) sensor measures the strength of the vacuum in the EGR vacuum circuit and sends a signal back to the electronic control module (ECM). If actual vacuum differs from the preferred vacuum as calculated by the ECM, the ECM will adjust the on-off intervals of the EGR valve to correct the flow of exhaust gas into the cylinders. This provides the required control of oxides of nitrogen emissions while retaining engine performance under all operating conditions. The ECM also uses the signal from the MAP sensor to control fuel delivery and ignition timing. Vacuum for the EGR system is taken from the throttle body and routed through a hose to the electronic vacuum regulator valve (EVRV) solenoid. The solenoid is controlled by the 435 circuit from the ECM. When the solenoid opens the electronic vacuum regulator valve vacuum reaches the EGR actuator through another vacuum hose and opens the EGR pintle valve to allow exhaust gas to flow into the inlet manifold. When the EVRV solenoid is released, the valve vents the EGR actuator to outside air to close the EGR pintle valve. A leak in the EGR (exhaust gas recirculation) vacuum system can upset the ECM’s programmed control of exhaust gas recirculation and adversely affected engine operation. Too much exhaust gas recirculation at idle or cruise can result in the engine stalling after closed throttle deceleration, surging during steady throttle cruising, or a rough idle. Too little exhaust gas flow allows combustion temperatures to become too high and bring about detonation ("spark knock") or an overheated engine. In addition, nitrous oxide emissions may be high enough to cause the vehicle to fail an emissions test. Because the source of a EGR system symptom might be traced to a mechanical or electrical condition as well as a faulty vacuum system, an effective systematic diagnosis procedure should examine all three categories of components - not just the vacuum system alone. Therefore, no exclusive vacuum system diagnosis procedures are provided here. For more information on the EGR system, refer to the 1991 “Fuel and Emissions Service Manual." DIAGNOSIS Conditions most likely to cause vacuum system problems include hoses that leak or become disconnected. With the engine running, either condition is easily detected from the hiss of air at the opening. Other common vacuum problems are kinked or obstructed hoses, hoses connected incorrectly or binding components. A vacuum pump can be used as a vacuum source to operate components and test the system. The built-in vacuum gage of the pump provides a means of checking for a vacuum leak as well. Once vacuum is applied to operate the component, the gage should hold steady until the vacuum is purposely released. On vacuum systems that are controlled by electrical or electronic switches, check for a blown fuse, wiring that is cracked, frayed or burned, and high resistance in connectors of the control circuits) before checking for a suspected vacuum system problem. S111 (SEE PAGE 11) I 450-.6 BLK/WHT W T JL • I ENGINE GROUND G100 EXHAUST GAS RECIRCULATION (EGR) VACUUM SYSTEMS V8 GASOLINE ENGINE C-65 S113 S116 C108 C196 C197 C105 C199 4 1. 2. 3. 4. 5. 6. Cold Advance Control Fast Idle Solenoid Fuel Shut-Off Valve Generator Glow Plug (RH) Cold Advance and Fast Idle Temperature Switch Figure 1 • Engine W iring Harenss -- RH Side (6.2L V 8 HD Diesel Engine) C-66 COMPONENT LOCATOR VIEWS 1. 2. Glow Plug (LH) Coolant Temperature Sender Figure 2 - Engine Wiring Harness -- LH Side (6.2L V8 HD Diesel Engine) 1. 2. 3. Figure 3 - Batteries and Cables (6.2L V8 HD Diesel Engine) C113 Low Coolant Warning Switch Map Sensor Battery Junction Block Figure 5 - Engine Wiring Harness to Cowl/Radiator (6.2L V8 HD Diesel Engine) C121 8 C128 1. 2. 3. 4. 5. 6. 7. 8. Glow Plug Controller Water in Fuel Sensor Fuel Heater Output Speed Sensor Transmission Input Speed Sensor Oil Pressure Sender Engine Speed Sensor C120 C104 C190 1. 2. C191 3. 4. 5. 6. 7. FRONT OF VEHICLE VIEW C172 Figure 4 - Engine Wiring Harness -- Rear (6.2L V8 HD Diesel Engine) Coil 7 Distributor Electronic Spark Module Input Speed Sensor Output Speed Sensor Transmission Engine Temperature Sensor C172 C174 12H31 Figure 6 - Engine Wiring Harness - LH Side (7.4L V8 Gasoline Engine) COMPONENT LOCATOR VIEWS C-67 S106 C115 ?I [ I—] C110 C111 C112 S108 12H11 S109 C175- C1061. 2. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10 . Idle Air Controller TP Sensor Injectors EVRV Cooling Fan Switch Starter Motor Knock Sensor Map Sensor Generator Coolant Temperature Sensor Fuel Pump Relay Brake Pressure Warning Switch Figure 8 - Engine W iring Harness to Cowl (7.4L V8 Gasoline Engine) C117 S103 12H32 C116 • C109 8 GJ03 C105 10 FRONT OF VEHICLE FRONT OF VEHICLE VIEW A VIEW B Figure 7 - Engine Wiring Harness, RH Side (7.4L V8 Gas Engine) C-68 COMPONENT LOCATOR VIEWS Figure 9 - Steering Column Switches 1. 2. 3. 4. 5. Horn Relay Cooling Fan Relay DRL Relay Hazard Flasher DRAC Module 6. 7. 8. 9. PCM S126 Dimmer Switch Ignition Switch Backup Lamp Switch C100 C208 IT] C210 1. Fuel Sender Assembly [I] C206 C207 C251 C205 C250 GT100 S214 VIEW 0 VIEW 12H10 Figure 10 - Engine Wiring Harness to Cowl (7.4L 0 12H47 va Gasoline Engine) 12H42 Figure 12 - Fuel Sender and Rear Lamp Wiring C209~ S1 ,.....,........-----7'~"'-~ / C208 ~~=---I~J o C200 1. 2. 1. 2. 3. 4. 5. 6. 7. 8. 9. Horn Relay DRL Relay DRAC Module Hazard Flasher rCM ALDL G109 Ignition Switch Dimmer Switch Backup Lamp Switch Battery Starter Motor S200 FRONT~ OF VEHICLE C214 Figure 11 - Engine Wiring Harness to Cowl (6.2L va HD Diesel Engine) 12H42 VIEW0 Figure 13 - Battery and Leads (7.4L va Gasoline Engine) COMPONENT LOCATOR VIEWS C-69 C O M P O N E N T L O C A T IO N Auxiliary Cooling Fan Relay ................ Auxiliary Cooling Fan Switch .............. Backup Lamp S w itc h ............................ Top LH side of shipping p a n e l..................... RH side of e n g in e .......................................... On steering c o lu m n ........................................ Page -- Figur .............. 69 10 .............. 68 7 .............. 69 10 69 11 .............. 67 3 .............. 67 3 69 13 .............. 67 5 .............. 68 8 .............. 66 1 Battery, F ro n t.......................................... Battery, Rear .......................................... RH frame rail behind engine ....................... RH frame rail behind engine ........................ Battery Junction B lo c k .......................... Brake Pressure Warning Switch ......... Cold Advance Control .......................... Cold Advance Fast Idle Temperature Switch ................................................. Coolant Temperature Sender (D ie s e l)................................................. Coolant Temperature Sensor (G asoline)............................................. Cruise Control S w itc h ............................ Distributor ............................................... DRAC Module ........................................ LH side of shipping panel ............................ Near master c y lin d e r...................................... Top front of e n g in e ........................................ Top RH front of engine ................................. LH side of steering column .......................... Top rear of e n g in e .......................................... Inside LH side of shipping p a n e l................ DRL R e la y ............................................... Top LH side of shipping p a n e l..................... .............. Engine Speed Sensor .......................... Engine Temperature S e n s o r................ ESC Module .......................................... E V R V ........................................................ Fast Idle Solenoid ................................. Fuel Heater ............................................. Fuel Pump Relay ................................... Fuel S e n d e r............................................. Fuel Shutoff Valve ................................. Generator (Diesel) ................................. Generator (Gasoline) ............................ Glow Plug #1 ........................................ Glow Plug # 2 ........................................ Glow Plug # 3 ........................................ Glow Plug # 4 ........................................ Glow Plug # 5 ........................................ Glow Plug #6 ........................................ Glow Plug # 7 ........................................ Glow Plug #8 ........................................ Glow Plug Controller ............................ Hazard Flasher ...................................... Rear of engine ............................................... .............. LH side of engine .......................................... .............. Top of engine near d is trib u to r..................... .............. RH front of e n g in e .......................................... .............. Top front of e n g in e ........................................ .............. Top rear of e n g in e ......... ? .............................. .............. LH frame rail behind shipping panel ......... .............. Inside fuel tank ............................................... .............. Top front of e n g in e ........................................ .............. Front of e n g in e ................................................. .............. Front of e n g in e ................................................. .............. LH side of engine .......................................... .............. RH side of e n g in e .......................................... .............. LH side of engine .......................................... .............. RH side of e n g in e .......................................... .............. LH side of engine .......................................... .............. RH side of e n g in e .......................................... .............. LH side of engine .......................................... .............. RH side of e n g in e .......................................... .............. Top LH rear of e n g in e ................................... .............. Top LH side of shipping p a n e l..................... .............. RH rear of engine .......................................... .............. LH front of e n g in e .......................................... .............. .............. .............. .............. .............. 66 66 1 Input Speed S e n s o r........................ LH side of transm ission.......................................... . . . 67 67 RH side of e n g in e ................................................... . . . 68 RH side of radiator ................................................. . . . 67 LH side of shipping panel ..................................... . . . 67 RH rear of e n g in e ................................................... . . . 68 LH rear of engine ................................................... . . . 67 LH side of transm ission.......................................... . . . 67 67 LH side behind shipping panel ............................ . . . 69 RH side of e n g in e ................................................... . .. 67 Knock Sensor ................................. Low Coolant Warning Switch . . . . . . . MAP Sensor (Diesel) ..................... MAP Sensor (Gasoline) ................ Oil Pressure S e n d e r....................... Output Speed Sensor ................... PCM ................................................. Starter M o t o r ................................... 68 7 9 67 69 69 69 69 67 67 67 6 10 11 10 11 Turn Signal S w itc h .......................... Water in Fuel S e n s o r ..................... Connectors: C100 ............................................. . . . 68 66 7 67 4 68 8 12 1 1 69 66 66 68 66 66 66 66 66 66 66 66 4 6 6 1 7 2 1 2 1 2 1 2 1 67 69 69 69 69 69 4 10 11 11 10 11 LH side of steering column .......................... .............. Top LH side of shipping p a n e l..................... .............. Idle Air Control A c tu a to r....................... Ignition C o i l ............................................. Ignition S w itc h ........................................ Top LH side of e n g in e ................................... .............. Top rear of e n g in e .......................................... .............. On steering c o lu m n ........................................ .............. 68 7 67 69 69 6 10 11 Injector # 1 ............................................... Top of e n g in e ................................................. .............. 68 7 COMPONENT LOCATOR INDEX Top of e n g in e ................................................................. TCM 68 68 Page - Figure 68 7 Injector # 2 ............................................... 2 Headlamp Dimmer Switch ................... Horn R e la y ............................................... C-70 COMPONENT LOCATION ................................................. C101 ................................. . . . C102 C103 C104 C105 ............................................. ............................................. . . . ............................................. ............................................. C106 C108 C109 C 110 ............................................. ............................................. ............................................. ............................................. cm ... ....... . . . ............................................. ............................................. ............................................. . . . ............................................. . . . . ........................................... C112 C113 C114 C115 C116 C117 ............................................. C119 ............................................. C120 ............................................. . . . C121 ................................. . . . C123 ............................................. C125 ............................................. C126 ............................................. C127 ............................................. C128 ............................................. C129 ............................................. C130 ............................................. C131 ............................................. LH side behind shipping panel ............................ Top of e n g in e .......................................................... LH side of steering column ................................... RH rear of e n g in e ................................................... . . . . . . . . . . . . 69 69 68 68 4 6 7 5 5 7 4 4 6 10 3 7 13 11 67 7 9 4 Top of LH cowl ........................................................ . . . 69 69 Front of LH cowl ..................................................... . . . 69 69 LH frame rail near f r o n t .......................................... . . . 68 At fuel pump re la y ................................................... . . . 68 At engine temperature s e n s o r.............................. . . . 67 At generator ............................................................ . . . 66 10 11 10 11 8 8 6 1 68 7 7 cooling fan s w itc h ............................................... coolant temperature s w itc h .............................. coolant temperature s e n d e r.............................. TP s e n s o r............................................................ RH in je c to r .......................................................... LH injector .......................................................... glow plug controller............................................ cold advance/fast idle temperature switch . . . idle air c o n tro lle r................................................. MAP sensor ........................................................ . .. ... ... . .. ... ... ... ... ... ... At knock sensor ..................................................... At oil pressure s e n d e r............................................ At electronic spark c o n tro l..................................... At ignition c o i l .......................................................... At engine speed sensor ........................................ Left of d is trib u to r..................................................... At low coolant warning switch .............................. At water in fuel s e n s o r............................................ At fuel heater .......................................................... At fast idle s o le n o id ................................................. At cold advance co n tro l.......................................... At fuel shutoff v a lv e ................................................. ... ... ... ... ... ... ... ... ... ... ... ... At At At At At At At At At At 68 66 68 68 68 68 67 66 68 67 68 68 2 7 7 7 7 4 1 7 5 7 7 4 67 67 67 67 67 67 67 67 5 4 4 66 66 66 1 1 1 6 fi 4 6 COMPONENT LOCATION C150 ................... ....................... Page - Figure LH side of front cro s s m e m b e r..................... .............. 69 69 .............. .............. .............. .............. .............. 68 68 68 68 C151 C153 C154 C155 C172 .... .......................... .......................... .......................... .......................... ....................... ....................... ....................... ....................... ....................... LH side of front cro s s m e m b e r..................... RH side of front cro ssm e m b er..................... At brake pressure warning switch .............. Center of front cro ssm e m b er........................ At transmission electronic control .............. C173 .................................................. ....................... At output speed s e n s o r................................. .............. C174 .......................... ....................... At input speed s e n s o r................................... .............. C175 C190 C191 C192 C193 C194 C195 C196 C197 C198 C199 C200 C201 C204 C205 .......................... .......................... At EVRV .................................................................................................................. ........................... At glow plug co ntro lle r .................................................................... ........................... At glow plug co n tro lle r................................... .............. C206 .......................... ....................... ............................................. ............................................. ....................... . . .......................... .......................... .......................... .......................... ....................... .................................................. ............................................. ........................... .............. .............. At #8 glow plug At # 7 glow plug ............................................. ............................ ...................................................................................... ........................... ........................... .................................................. .................................................. ............................................ .................................................. ............................................. .......................... ....................... .................. ....................... .................................................. ............................................ .................................................. ............................................ At At At At At At # 3 glow plug ...................................................................................... #1 glow plug ............................................. ignition s w itc h ...................................................................................... ignition s w itc h ...................................................................................... ALDL ................................................................................................................. DRAC m o d u le ...................................................................................... Base of steering column C207 .................................................. ............................................ LH frame rail behind cowl C208 .................................................. ............................................ At DRL relay C209 C210 C211 C212 C213 C214 C215 C220 C222 C244 C250 C251 .................................................. ....................... .................................................. ............................................ .................. ....................... .................................................. ............................................ .................................................. ............................................ ........................................................... At horn re la y .................................................................................................... At cooling fan r e la y ............................................................................. Lower left of steering c o lu m n .............................................. At hazard fla s h e r ...................................................................................... At headlamp dimmer s w itc h .................................................. .................................................. ............................................ .................................................. ............................................ .................................................. ............................................ ........................... ........................... ........................... ............................................ ............................................ ............................ ............................ .................................................................................................... .................................................. ....................... ........................... ............................ Lower left of steering c o lu m n .............................................. At backup lamp switch ................................................................ ....................... ........................... ....................................................... ....................... .................................................. ........................... LH frame rail near cowl ................................................................ LH cowl top center ............................................................................. Base of steering column ........................................................... LH front frame r a i l .......................................... LH front frame r a i l .................................................................................. ........................... ........................... ........................... ........................... ........................... ........................... ............................ ........................... ........................... ........................... ........................... ........................... 67 67 67 67 67 67 68 67 67 66 66 66 66 66 66 66 66 10 11 8 8 8 8 6 4 6 4 6 7 4 4 69 69 69 69 69 68 9 69 69 69 69 69 69 69 69 69 69 69 69 69 69 69 69 69 10 10 11 10 11 10 11 10 10 11 10 11 10 10 11 10 11 8 8 8 10 10 69 69 Page -- Figure C252 ........................................ C253 ........................................ C401 ........................................ C402 ........................................ Grommets: GT100 ...................................... LH front frame r a i l ........................................................... LH front frame r a i l ........................................................... At fuel level s e n d e r ......................................................... LH side of rear crossm em ber........................................ 69 69 69 69 11 11 12 12 LH side of c o w l................................................................ 69 69 GT101 ...................................... Grounds: G100 ........................................ G101 ........................................ G103 ........................................ G109 ........................................ G110 ........................................ Injector b o d y .................................................................... 68 10 11 7 4 1 1 1 1 2 2 2 2 11 11 11 10 11 68 68 68 COMPONENT LOCATION G4Q0 ........................................ Splices: 510 0 510 1 510 2 510 3 510 4 S 1 0 6 .......................................... 510 8 510 9 511 0 511 511 511 511 1 2 3 4 Lower LH side of c o w l.................................................... Top front of e n g in e ......................................................... At alternator bracket ...................................................... Lower LH side of c o w l.................................................... RH frame rail below rear battery ................................. LH crossmember in front of fuel t a n k .......................... Battery junction block .................................................... Battery junction block .................................................... Battery junction block .................................................... RH lower side of engine ............................................... Battery junction block .................................................... LH frame rail behind cowl ............................................. LH frame rail behind cowl ............................................. Front center of e n g in e .................................................... LH side of transmission (d ie s e l)................................... LH side of cowl (g a s o lin e )............................................. Front RH side of engine ............................................... Rear center top of engine ............................................. LH top of e n g in e ............................................................. LH side of c o w l............................................................... 69 69 67 69 69 10 1 7 11 3 13 12 67 67 67 5 5 5 66 68 68 7 67 5 68 68 68 8 8 67 6 8 68 68 67 68 66 68 69 7 7 4 7 2 8 10 RH side of c o w l............................................................... 68 8 69 511 6 S 1 2 6 ........................................ 515 0 515 1 515 2 515 3 515 4 515 6 515 7 S200 ........................................ LH top rear of engine .................................................... LH side of c o w l............................................................... RH lower side of engine ............................................... Rear center of engine .................................................... Rear center of engine .................................................... LH side of tra n sm issio n ................................................. LH top rear of engine .................................................... RH top side of c o w l........................................................ LH top side of c o w l........................................................ Cowl near steering column .......................................... 66 11 2 10 1 5204 5205 521 3 521 4 Lower Lower Lower Lower 521 Lower RH corner 511 5 5 RH RH RH RH corner corner corner corner 69 66 67 67 67 67 69 69 69 69 behind cowl ...................................... 69 behind cowl ...................................... 69 behind cowl ...................................... 69 behind cowl ...................................... 69 69 behind cowl ...................................... 69 COMPONENT LOCATER INDEX 4 4 4 4 11 11 10 11 10 10 10 10 11 10 C-71 COMPONENT LOCATION 8216 . 521 ....................... 6 521 ....................... 7 8217 . . 8250 S250 ....................... .......................................... C-72 Page -- Figure LH top of cowl . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 69 Top LH corner comer of cowl. cowl . . . . . . . . . . . . . . . . . . . . .. 69 Top LH ·corner corner of cowl. cowl . . . . . . . . . . . . . . . . . . . . .. 69 COMPONENT LOCATER INDEX 11 10 11 Abbreviation List ................................................... 10 Air Conditioning, Front Manual, R/V ................ A-94 Air Conditioning, Provisions For, P Motorhome ................................................... C-50 Air Conditioning, Rear, R /V ................................ A-95 Alarm, Audio, R /V .................................................A-111 AM Radio, R / V ......................................................A-144 Antilock Brakes, Rear Wheel, R / V .....................A-116 Audio Alarm, R / V .................................................A-111 Auxiliary Battery, R/V ..........................................A-22 Auxiliary Cooling Fan, R/V ................................ A-89 Auxiliary Cooling Fan, P M o torho m e ................ C-49 Auxiliary Fuel Tank and Fuel Tank Selector Switch, Diesel, R/V ......................... A-81 Auxiliary Fuel Tank and Fuel Tank Selector Switch, Gasoline, R/V .....................A-80 Auxiliary Heater, R/V ..........................................A-99 Backup Lamps (Fleetside and Wideside), R /V ...................................................................... A-154 Backup Lamps (Stepside), R /V ......................... A-155 Backup Lamps (Suburban and Utility), R /V ...................................................................... A-155 Backup Lamps, P Commercial ......................... B-77 Backup Lamps, P M otorhom e............................ C-63 Basic Electricity ..................................................... 4 Battery, Auxiliary, R /V ..........................................A-22 Block, Fuse, R/V .................................................A-14 Block, Fuse, Gasoline W/Man Trans, P C o m m e rcial................................................... B-10 Block, Fuse, Gasoline W/Auto Trans, P C o m m e rcial................................................... B-11 Block, Fuse, Gasoline, P Motorhome .............. C -8 Block, Fuse, Diesel W/Man Trans, P C o m m e rcial................................................... B-12 Block, Fuse, Diesel W/Auto Trans, P C o m m e rcial................................................... B-13 Block, Fuse, Diesel, P Motorhome ................... C-9 Brake Booster Vacuum System, Power, R/V . . A-164 Brake Warning System, School Bus, P C o m m e rcial................................................... B-74 Brake Warning System, R / V .............................. A-114 Brake Warning System Without Rear Wheel Antilock Brakes, R /V ............................A-115 Bulb Data, R / V ..................................................... A-15 Bulb Data, P C o m m e rcia l................................... B-14 Bulb Data, P Motorhome i ................................ C-10 Camper and Trailer Wiring, R/V ....................... A-160 Cargo Lamp, R / V .................................................A-120 Center, Convenience, R/V ................................ A-21 Charge, Start and, Diesel, R/V ......................... A-56 Charge, Start and, Diesel, P Commercial . . . . B-41 Charge, Start and, Diesel, P M otorhom e......... C-31 Charge, Start and, Gasoline, R/V .....................A-55 Charge, Start and, Gasoline, P Commercial . . B-40 Charge/Start and, Gasoline, P Motorhome . . . C-30 Circuit Diagrams .................................................... 3 Circuit M a lfu n c tio n s ............................................... 4 Circuit Operation .................................................... 3 Circuit Wiring Repair Procedures ....................... 6 Cluster, Instrument Panel, R/V ..........................A-103 Cluster, Instrument Panel, P Commercial . . . . B-69 Cluster, Instrument Panel, P M o torho m e ......... C-55 Component Locations .......................................... 3 Component Locater Index, R /V ..........................A-194 Component Locater Index, P Commercial . . . . B-87 Component Locater Index, P Motorhome . . . . C-70 Component Locator Views, R/V ....................... A-166 Component Locator Views, P Commercial . . . B-81 Component Locator Views, P Motorhome . . . . C -66 Conditioning, Air, R /V .......................................... A-94 Conditioning, Air, Provisions For, P M o to rh o m e ....................................................C-50 Connectors, Metri-Pack ........................................ 8 Connectors, W eather-P ack................................... 8 Contents, Table o f ................................................. 1 Control, Cruise, R / V .............................................A-124 Control, Cruise, P Motorhome ..........................C-52 Control Module, Electronic, Pinouts, Diesel, R / V ........................................................ A-62 Control Module, Electronic, Pinouts, Gasoline, R / V ....................................................A-57 Control Module, Electronic, Pinouts, Gasoline, P Commercial ................................. B-43 Control Module, Powertrain, Pinouts, Gasoline, R / V ....................................................A -66 Control Module, Powertrain, Pinouts, Gasoline, P Commercial ................................. B-49 Control Module, Transmission, Pinouts, Gasoline, P M otorhom e................................... C-33 Control Module, Transmission, Pinouts, Diesel, R / V ........................................................ A-67 Control Module, Transmission, Pinouts, Diesel, P Commercial ..................................... B-55 Control Module, Powertrain, Pinouts, Diesel, P M otorhom e........................................C-39 Control Module, Inputs, Diesel, Electronic, R / V ................................................. A-63 Control Module, Inputs, Gasoline, Electronic, R/V ................................................. A-58 Control Module, Inputs, Gasoline, Electronic, P Commercial .............................. B-44 Control Module, Inputs, Gasoline, Powertrain, R /V ................................................. A -68 Control Module, Inputs, Gasoline, Powertrain, P C o m m e rcial.............................. B-50 Control Module, Inputs, Gasoline, Powertrain, P Motorhome ...............................C-34 Control Module, Outputs, Diesel, Electronic, R / V ................................................. A-64 Control Module, Outputs, Gasoline, Electronic, R/V ................................................. A-60 Control Module, Outputs, Gasoline, Electronic, P Commercial ...............................A-46 Control Module, Outputs, Gasoline, Powertrain, R /V ................................................. A-70 Control Module, Outputs, Gasoline, Powertrain, P C o m m e rcial............................... B-52 Control Module, Outputs, Gasoline, Powertrain, P Motorhome ...............................C-36 Control Module, Outputs, Diesel Transmission, R /V .............................................A-72 Control Module, Outputs, Diesel Transmission, P C o m m e rcial.................................................... B-56 Control Module, Outputs, Diesel Transmission, P M o to rh o m e ....................................................C-40 Controller (DRAC) Module, Digital Ratio Adapter, R/V .......................................... A-75 Controller (DRAC) Module, Digital Ratio Adapter, W/Man or Auto Trans and Trans and Diesel W/Auto Trans, P Commercial . . . B-64 Controller (DRAC) Module, Digital Ratio Adapter, Diesel W/Man Trans, P C o m m e rcial.................................................... B-65 Controller (DRAC) Module, Digital Ratio Adapter, P Motorhome ................................... C-42 Convenience Center, R / V ................................... A-21 Cooling Fan, Auxiliary, R / V ................................. A-89 Cooling Fan, Auxiliary, P Motorhome .............. C-49 Cruise Control, R/V .............................................A-124 Cruise Control, P M o to rh o m e ............................ C-52 Data, Bulb, R/V ....................................................A-15 Data, Bulb, P C om m ercial................................... B-14 Data, Bulb, P M o to rh o m e ................................... C-10 Daytime Running Lamps (Canada Only), R /V .......................................................................A-22 Daytime Running Lamps (Canada Only), P C o m m e rcial.................................................... B-28 Daytime Running Lamps (Canada Only), P Motorhome ....................................................C-18 Defogger, Rear, R / V .............................................A-146 Diagnosis C h a r ts .................................................... 4 Diagrams, C ir c u it.................................................... 3 Diesel, Electronic Control Module, R / V ............A-63 Diesel Engine Fuel Controls, P Commercial . . B-63 Diesel Engine Fuel Controls, P Motorhome . . . C-47 Diesel Engine Fuel Controls, 6.2L, R / V ............A-87 Diesel Engine Fuel Controls, 6.2L HD, R /V .......................................................................A -88 Diesel, Transmission Control Module, R/V . . . . A-72 Diesel, Transmission Control Module, P C o m m e rcial.................................................... B-56 Diesel, Transmission Control Module, P M o to rh o m e ....................................................C-40 Diesel, Transmission Control Module, Pinouts, R / V ...................................................... A-67 Diesel, Transmission Control Module, Pinouts, P Commercial ................................... B-55 Diesel, Transmission Control Module, Pinouts, P M otorhom e......................................C-39 Digital Ratio Adapter Controller (DRAC) Module, R / V ...................................................... A-75 Digital Ratio Adapter Controller (DRAC) Module, Gasoline W/Man Trans or Auto Trans and Diesel W/Auto Trans, P Commercial ........................ B-64 Digital Ratio Adapter Controller (DRAC) Module, Diesel W/Man Trans, P Com m ercial.............. B-65 Digital Ratio Adapter Controller (DRAC) Module, P M otorhom e......................................C-42 Distribution, Power, Diesel, R /V ..........................A-12 Distribution, Power, Diesel W/Man Trans, P C o m m e rcial.................................................... B-6 Distribution, Power, Diesel W/Auto Trans, P M o to rh o m e ...................................................... B-7 Distribution, Power, Diesel W/Auto Trans, P Motorhome .................................................... C-5 Distribution, Power, Diesel Driveaway P C om m ercial.................................................... B-8 Distribution, Power, Diesel Driveaway, P M o to rh o m e .................................................... C-7 Distribution, Power, Gasoline, R /V ..................... A-10 Distribution, Power, Gasoline W/Man Trans, P C o m m e rcial.................................................... B-4 Distribution, Power, Gasoline W/Auto Trans, P Commercial ........................................ B-5 Distribution, Power, Gasoline W/Auto Trans, P M o to rh o m e ........................................ C-4 Distribution, Power, Gasoline Driveaway P C om m ercial.................................................... B-9 Distribution, Power, Diesel Driveaway, P M o to rh o m e .................................................... C-6 Dome Lamps, Instrument Panel Compartment Lamp and Lighted Vanity Mirror, R /V ............A-119 Dome Lamps, Provisions For, P Motorhome . . C-59 Door Locks, 2-Door, (With Power Outside Rearview Mirrors), Power, R / V ....................... A-131 Door Locks, 2-Door, (Without Power Outside Rearview Mirrors), Power, R / V ....................... A-130 Door Locks, 4-Door, (With Power Outside Rearview Mirrors), Power, R / V ....................... A-132 Door Locks, 4-Door, (Without Power Outside Rearview Mirrors), Power, R / V ....................... A-133 Drive, Four-Wheel, R / V ........................................ A-126 Electrical Test E qu ip m e n t...................................... 4 Electricity, B a s ic ...................................................... 4 GENERAL INDEX 1 Electronic Control Module Pinouts, Diesel, R /V .......................................................................A-62 Electronic Control Module Pinouts, Gasoline, R / V .......................................................................A-57 Electronic Control Module Pinouts, Gasoline, P C o m m e rcial.................................................... B-43 Electronic Control Module - Inputs, Diesel, R / V .......................................................................A-63 Electronic Control Module - Inputs, Gasoline, R / V .......................................................................A-58 Electronic Control Module - Inputs, Gasoline, P C o m m e rcial.................................................... B-44 Electronic Control Module - Outputs, Diesel, R / V .......................................................................A-64 Electronic Control Module - Outputs, Gasoline, R /V .......................................................................A-60 Electronic Control Module - Outputs, Gasoline, P C o m m e rcial.................................................... B-46 Four-Wheel Drive, R/V ........................................ A-126 Forward Lamp Harness, P C om m ercial............B-24 Forward Lamp Harness, P M o to rh o m e ............C-14 Forward Lamp Harness, W/DRL, P C o m m e rcial.................................................... C-27 Forward Lamp Harness, W/DRL, P Motorhome .................................................... C-20 Front Manual Air Conditioning, R /V ...................A-94 Front Park, Marker, Roof and Hazard Lamps, R /V ........................................................ A-33 Fuel Control and Idle Air Control, Gasoline, R / V ....................................................A-78 Fuel Control and Idle Air Control, Gasoline, P C om m ercial.................................................... B-54 Fuel Controls, Diesel Engine, P Commercial . . B-63 Fuel Controls, Diesel Engine, P Motorhome . . C-47 Fuel Controls, (6.2L), Diesel Engine, R /V .......................................................................A-87 Fuel Controls, (6.2L HD), Diesel Engine, R /V .......................................................................A -88 Fuel Handling, Gasoline, Hot, R /V ..................... A-79 Fuel Tank Selector Switch, Diesel, Auxiliary Fuel Tank and, R / V ..........................A-81 Fuel Tank Selector Switch, Gasoline, Auxiliary Fuel Tank and, R / V ..........................A-80 Fuse Block, R / V ....................................................A-14 Fuse Block, Diesel W/Man Trans, P C o m m e rcial.................................................... B-12 Fuse Block, Diesel W/Auto Trans, P C o m m e rcial.................................................... B-13 Fuse Block, Diesel W/Auto Trans, P M o to rh o m e .................................................... C-9 Fuse Block, Gasoline W/Man Trans, P C o m m e rcial.................................................... B-10 Fuse Block, Gasoline W/Auto Trans, P C o m m e rcial.................................................... B-11 2 GENERAL INDEX Fuse Block, Gasoline W/Auto Trans, P M o to rh o m e .................................................... C -8 Fuse Block ID and Bulb Data, R/V ...................A-15 Gages (Fleetside), Instrument Panel, R/V . . . . A-109 Gages (Suburban and Utility), Instrument Panel, R/V .........................................................A-108 Gages, Instrument Panel, P C o m m e rcial......... B-72 Gages, Instrument Panel, P M o to rh o m e ......... B-57 Glow Plugs, R /V ....................................................A-84 Glow Plugs, P C o m m e rcia l................................. B-60 Glow Plugs, P Motorhome ................................. C-44 Ground Distribution, Diesel, R / V ........................A-18 Ground Distribution, Diesel W/Man Trans, P C o m m e rcial.................................................... B-19 Ground Distribution, Gasoline W/Auto Trans, P C o m m e rcial.................................................... B-20 Ground Distribution, Diesel, P Motorhome . . . C-12 Ground Distribution, Forward Lamps, P C o m m e rcial.................................................... B-15 Ground Distribution, Gasoline, R / V ...................A-16 Ground Distribution, Gasoline W/Man Trans, P C om m e rcial.................................................... B-16 Ground Distribution, Gasoline W/Auto Trans, P C om m e rcial.................................................... B-17 Ground Distribution, Gasoline, P Motorhome . C-11 Ground Distribution, Rear, P Commercial . . . . B-21 Harness, Forward Lamps, P Commercial . . . . B-24 Harness, Forward Lamps, P M o to rh o m e ......... C-14 Harness, Forward Lamps W/DRL, P C om m e rcial.................................................... B-27 Harness, Forward Lamps W/DRL, P Motorhome ....................................................C-20 Harness, Rear Lamps, P C o m m e rc ia l.............. B-76 Harness, Rear Lamps, P Motorhome .............. C-61 Harnesses, Vacuum, R/V ................................... A-164 Hazard Lamps, (All Models), Rear, R / V ............A-35 Hazard Signal Lamps, P Commercial .............. B-32 Hazard Signal Lamps, P M otorhom e ................ C-22 Hazard Lamps with Quad Halogen Headlamps, R / V ............................................... A-36 Hazard Lamps, Front Park, Marker, Roof and, R /V ............................................................. A-33 Headlamps - Base, R/V ......................................A-25 Headlamps - Base, P Commercial ................... B-23 Headlamps - Base, P M o to rh o m e ..................... C-15 Headlamps With Daytime Running Lamps, R /V ...................................................................... A-26 Headlamps with Daytime Running Lamps, P C om m ercial.................................................... B-28 Headlamps with Daytime Running Lamps, P Motorhome ....................................................C-18 Headlamps, Quad Halogen, R /V ........................A-32 Heater, Auxiliary, R / V .......................................... A-99 Heater, R/V ...........................................................A-96 Horns, R /V ............................................................. A-49 Horns, P C o m m e rcia l.......................................... B-36 Horns, P Motorhome .......................................... C-26 Hot Fuel Handling, R /V ........................................ A-79 How To Use This M a n u a l..................................... 3 Idle Air Control, Fuel Control and, R/V ............A-78 Idle Air Control, Fuel Control and, P C o m m e rcial.................................................... B-54 Ignition, Gasoline, R/V ........................................ A-76 Ignition, Gasoline, P Commercial ..................... B-42 Ignition, Gasoline, P M o torho m e ....................... C-32 Index, Component Locater, R/V ....................... A-94 Index, Component Locater, P Commercial . . . B-87 Index, Component Locater, P Motorhome . . . . C-70 Index, Symptoms, R/V .......................................... A -8 Index, Symptoms, P Commercial ....................... B-3 Index, Symptoms, P M o torho m e....................... C-3 Indicator Lamps (Fleetside), R /V ....................... A-106 Indicator Lamps (Suburban and Utility), R /V ...................................................................... A-104 Indicator Lamps, P Commercial ....................... B-70 Indicator Lamps, P M o torho m e ..........................C-56 Injection, Throttle Body, R / V .............................. A-77 Injection, Throttle Body, P C o m m e rc ia l............ B-48 Injection, Throttle Body, P Motorhome ............C-38 Instrument Panel Cluster, R /V ............................ A-103 Instrument Panel Cluster, P C o m m e rcial......... B-69 Instrument Panel Cluster, P Motorhome ......... C-55 Instrument Panel Indicators, R /V ....................... A-104 Instrument Panel Indicators, P Commercial . . . B-70 Instrument Panel Indicators, P Motorhome . . . C-56 Instrument Panel Gages (Fleetside, Wideside, Crew Cab), R /V .............................. A-106 Instrument Panel Gages (Suburban and Utility), R / V ........................................................ A-108 Instrument Panel Gages, P Commercial ......... B-71 Instrument Panel Gages, P M otorhom e............C-57 Instrument Panel Lamps (Fleetside), R /V ...................................................................... A-109 Instrument Panel Lamps (Suburban and Utility), R / V ........................................................ A-110 Instrument Panel Lamps, P C o m m e rc ia l......... B-72 Instrument Panel Lamps, P Motorhome ......... C-58 In tro d u c tio n ............................................................. 3 Key-ln and Lights-On Warning Buzzer, R /V ...................................................................... A-113 Lamp, Cargo, R/V ...............................................A-121 Lamp (Fleetside and Wideside), License, R /V ...................................................................... A-159 Lamp (Suburban and Utility), License, R /V ...................................................................... A-159 Lamps, Turn Signal, R /V ..................................... A-44 Lamps, Turn Signal, P C om m ercial................... B-34 Lamps, Turn Signal, P M o to rh o m e ...................C-24 Lamps (Fleetside and Wideside), Backup, R /V ...................................................................... A-154 Lamps, Backup, P C om m ercial.......................... B-77 Lamps, Backup, P M o to rh o m e ..........................C-63 Lamps (Fleetside and Wideside), Park and Marker, R/V ...................................................... A-35 Lamps, Front Park, Marker, Roof and Hazard, R/V ...................................................... A-34 Lamps, Park and Marker Signal, P C om m ercial.................................................... B-31 Lamps, Park and Marker Signal, P M o to rh o m e ....................................................C-22 Lamps, Rear Exterior, R/V ................................. A-149 Lamps, Roof Marker, R / V ................................... A-34 Lamps (Stepside), Backup, R/V ....................... A-154 Lamps (Suburban and Utility), Backup, R N ...................................................................... A-157 Lamps (Suburban and Utility), Indicator, R /V ...................................................................... A-104 Lamps (Suburban and Utility), Park and Marker, R/V ...................................................... A-159 Lamps (With Quad Halogen), Hazard, R/V . . . A-38 License Lamp (Fleetside and Wideside), R /V ...................................................................... A-159 License Lamp (Suburban and Utility), R /V ...................................................................... A-158 Locations, C o m p o n e n t.......................................... 3 Malfunctions, C irc u it............................................... 4 Manual, How To Use This ................................... 3 Marker Lamps (Fleetside and Wideside), Park and, R /V ....................................................A-35 Marker Lamps (Suburban and Utility), Park and, R /V ....................................................A-34 Marker Signal Lamps, Park and, P C om m ercial.................................................... B-31 Marker Signal Lamps, Park and, P M o to rh o m e ....................................................C-22 Marker, Roof and Hazard Lamps, Front Park, R/V ...........................................................A-34 Metri-Pack C o n ne ctors .......................................... 8 Operation, C irc u it.................................................... 3 Panel Doors, Rear Defogger, R / V ..................... A-147 Park and Marker Lamps (Fleetside and Wideside), R / V ................................................. A-157 Park and Marker Lamps (Suburban and Utility), R / V ........................................................ A-156 Park and Marker Signal Lamps, P C om m ercial.................................................... B-31 Park and Marker Signal Lamps, P M o to rh o m e ....................................................C-22 Phantom View, R/V ............................................... A-2 Phantom View, P C om m ercial...............................B-2 Phantom View, P M o to rh o m e ............................ C-2 Plugs, Glow, R/V ................................................. A-84 Plugs, Glow, P Commercial .............................. B-60 Plugs, Glow, P M o to rh o m e ................................ C-44 Power Brake Booster Vacuum System, R/V . . . A-164 Power Distribution - Diesel, R/V ....................... A-12 Power Distribution, Diesel W/Man Trans, P C o m m e rcial......................................................B-6 Power Distribution, Diesel W/Auto Trans, P C o m m e rcial......................................................B-7 Power Distribution, Diesel W/Auto Trans, P M o to rh o m e ................................................... C-5 Power Distribution, Diesel Driveaway, P C o m m e rcial..................................................... B-8 Power Distribution, Diesel Driveaway, P M o to rh o m e ................................................... C-7 Power Distribution - Gasoline, R/V .................. A-10 Power Distribution, Gasoline W/Man Trans, P C o m m e rcial..................................................... B-4 Power Distribution, Gasoline W/Auto Trans, P C o m m e rcial..................................................... B-5 Power Distribution, Gasoline W/Auto Trans, P M o to rh o m e ................................................... C-4 Power Distribution, Gasoline Driveaway, P C o m m e rcial..................................................... B-9 Power Distribution, Gasoline Driveaway, P M o to rh o m e ................................................... C -6 Power Door Locks, 2-Door (With Power Outside Rearview Mirrors), R / V .....................A-131 Power Door Locks, 2-Door (Without Power Outside Rearview Mirrors), R / V .....................A-130 Power Door Locks, 4-Door (With Power Outside Rearview Mirrors), R / V .....................A-132 Power Door Locks, 4-Door (Without Power Outside Rearview Mirrors), R / V .....................A-134 Power Door Locks and Power Mirrors, R /V ...................................................................... A-131 Power Mirrors and Power Door Locks, R /V ...................................................................... A-131 Power Outside Rearview Mirrors, R / V ..............A-129 Power Rear Window, R / V ...................................A-142 Power Windows, 2-Door, R / V ............................A-139 Power Windows, 4-Door, R / V ............................A-140 Power Windows, R/V ..........................................A-136 Powertrain Control Module Inputs Gasoline, R / V ................................................... A -68 Powertrain Control Module Inputs Gasoline, P C o m m e rc ia l................................ B-50 Powertrain Control Module Inputs Gasoline, P M otorhom e...................................C-34 Powertrain Control Module Outputs Gasoline, R / V ...................................................A-70 Powertrain Control Module Outputs Gasoline, P C o m m e rc ia l................................ B-52 Powertrain Control Module Outputs Gasoline, P M otorhom e...................................C-36 Powertrain Control Module Pinouts, R / V ......... A -66 Powertrain Control Module Pinouts, P C om m e rcial....................................................A-49 Powertrain Control Module Pinouts, P M o to rh o m e ................................................... A-33 Pulse Wiper/Washer, R / V ................................... A-50 Radio, AM ETR, R /V ............................................ A-144 Radio, Stereo, R / V ...............................................A-145 Radio, R / V ............................................................. A-143 Rear Air Conditioning, R / V .................................A-95 Rear Defogger - Panel Doors, R/V ...................A-147 Rear Defogger, R/V .............................................A-146 Rear Defogger - Tailgate, R /V ............................ A-148 Rear Exterior Lamps, R / V ................................... A-149 Rear Hazard Lamps, R/V ................................... A-35 Rear Wheel Antilock Brakes, R/V ..................... A-116 Rear Window, Power, R /V ................................... A-142 Rearview Mirrors, Power Outside, R /V .............. A-129 Regular Production Option (RPO) L is t................ 10 Repair Procedures, Circuit W irin g ....................... 6 Roof and Hazard Lamps, Front Park, Marker, R/V ......................................................A-34 Roof Marker Lamps, R/V ................................... A-40 Safety Belt Warning Buzzer, R /V ....................... A-112 Special T o o ls ........................................................... 9 Start and Charge, Diesel, R /V ............................ A-56 Start and Charge, Diesel, P C o m m e rcial......... B-41 Start and Charge, Diesel, P Motorhome ......... C-31 Start and Charge, Gasoline, R /V ....................... A-55 Start and Charge, Gasoline, P Commercial . . . B-40 Start and Charge, Gasoline, P Motorhome . . . C-30 Symptoms Index, R /V ............................................ A -8 Symptoms Index, P Commercial . ..................... B-3 Symptoms Index, P Motorhome ....................... C-3 Table of Contents ................................................. 1 Tailgate, Rear Defogger, R/V ............................ A-148 Tailiamps (Fleetside and Wideside), R /V ...................................................................... A-151 Tailiamps (Stepside), R / V ................................... A-152 Tailiamps (Suburban and Utility), R /V ...................................................................... A-150 Tail, Rear Marker and License Lamps, P C om m ercial.................................................... B-78 T a ilia m p s............................................................... C-62 Test Equipment, Electrical ................................... 4 Throttle Body Injection, R/V ...............................A-77 Throttle Body -Injection, P Commercial ............ B-48 Throttle Body Injection, P M o to rh o m e .............. C-38 Tools, Special ........................................................ 9 Trailer Wiring, Camper and, R / V ....................... A-160 Transmission Control Module Pinouts, R /V ...................................................................... A-67 Transmission Control Module Pinouts, P C om m ercial.................................................... B-55 Transmission Control Module Pinouts, P Motorhome . ............................................... C-39 Transmission Control Module, Diesel, R /V .......................................................................A-72 Transmission Control Module, Diesel, P C om m ercial.................................................... B-56 Transmission Control Module, Diesel, P M o to rh o m e ......... ..........................................C-40 Transmission Converter Clutch Detent Solenoid (5.7L), R /V ............................ A-74 Turn Signal Lamps, R / V ......................................A-44 Turn Signal Lamps, P .C o m m e rcia l................... B-34 Turn Signal Lamps, P M otorhom e..................... C-24 Underhood Lamp, R / V ........................................A-121 Vacuum Systems, R/V ........................................ A-164 Vacuum Systems, P Commercial ..................... B-79 Vacuum Systems, P M o torho m e ........................C-64 View, Phantom, R / V ............................................... A-2 View, Phantom, P Commercial ............................ B-2 View, Phantom, P M otorhom e............................ C-2 Views, Component Locator, R / V ....................... A-166 Views, Component Locator, P Commercial . . . B-81 Views, Component Locator, P Motorhome . . . C -66 Warning Buzzer, Key-ln and Lights-On, R /V .......................................................................A-113 Warning Buzzer, Safety Belt, R/V ..................... A-112 Warning System Without Rear Wheel Antilock Brakes, Brake, R /V ............................ A-115 Weather-Pack Connectors ................................... 8 Windows, Power, R/V . ........................................ A-136 Windows, 2-Door, Power, R /V ............................ A-139 Windows, 4-Door, Power, R /V ............................ A-140 Windshield Wiper/Washer, P Commercial . . . . B-38 Windshield Wiper/Washer, P Motorhome . . . . C-28 Wiper/Washer, Pulse, R /V ................................... A-50 Wiring, Camper and Trailer, R / V ........................A-160 GENERAL INDEX 3