GMC Cab & Chassis C3500 (1985-2000) yel Wiring diagrams

ABS FUSE ABS IND. BATTERY PUMP MOTOR GROUND BLK WIRE BLK/WHT WIRE BRAKE FUSE 18 BRAKE IND BRAKE PRESSURE WARNING SWITCH (UNDERSIDE OF EBCM) BRAKE SW OUTPUT BRN WIRE DAYTIME RUNNING LAMP (DRL) MODULE (BEHIND LEFT SIDE OF DASH) DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) ENGINE CONTROLS SYSTEM FRONT AXLE ACTUATOR (ON RIGHT REAR OF FRONT DRIVE AXLE) FUSE/RELAY BLOCK (LEFT REAR OF ENGINE COMPT) GAUGES FUSE 4 HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) IGNITION ABS IND GROUND BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T NEAR BREAKOUT TO TRANSFER CASE RELAY) PNK WIRE PPL PPL DATA LINK CONNECTOR (DLC) (LEFT OF STEERING COLUMN) PPL PPL 1807 680 PPL SERIAL DATA PPL/WHT WIRE RED WIRE RIGHT FRONT WHEEL SPEED SENSOR SENSOR LOW SENSOR LOW SENSOR HIGH SENSOR HIGH 830 872 STOPLAMP SWITCH (TOP OF BRAKE PEDAL) TAN WIRE TAN/WHT WIRE TRANSFER CASE CONTROL MODULE (ON STEERING COLUMN SUPPORT BRACKET) TRANSMISSIONS SYSTEM VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (VSS) (LEFT SIDE OF TRANSMISSION/ TRANSFER CASE) VEHICLE SPEED SIG VSS VSS SIG BRAKE LAMP IND OUT SERIAL DATA LINE BRAKE IND INPUT EBCM GROUND YEL WIRE YEL/BLK WIRE

ABS FUSE ABS IND. BATTERY PUMP MOTOR GROUND BLK WIRE BLK/WHT WIRE BRAKE FUSE 18 BRAKE IND BRAKE PRESSURE WARNING SWITCH (UNDERSIDE OF EBCM) BRN WIRE DAYTIME RUNNING LAMP (DRL) MODULE (BEHIND LEFT SIDE OF DASH) DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) ENGINE CONTROLS SYSTEM FRONT AXLE ACTUATOR (ON RIGHT REAR OF FRONT DRIVE AXLE) FUSE/RELAY BLOCK (LEFT REAR OF ENGINE COMPT) GAUGES FUSE 4 HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) IGNITION ABS IND GROUND BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LT BLU WIRE LT GRN WIRE M/T NEAR BREAKOUT TO TRANSFER CASE RELAY) PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (BEHIND RIGHT SIDE OF DASH) PPL PPL DATA LINK CONNECTOR (DLC) (LEFT OF STEERING COLUMN) PPL PPL 1807 680 PPL SERIAL DATA RED WIRE RIGHT FRONT WHEEL SPEED SENSOR SENSOR LOW SENSOR LOW SENSOR HIGH SENSOR HIGH 830 872 SERIAL DATA STOPLAMP SWITCH (TOP OF BRAKE PEDAL) TAN WIRE TAN/WHT WIRE TRANSFER CASE CONTROL MODULE (ON STEERING COLUMN SUPPORT BRACKET) TRANSMISSIONS SYSTEM VSS OUT VSS SIG BRAKE LAMP IND OUT SERIAL DATA LINE BRAKE IND INPUT EBCM GROUND YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS SENS HI IN A/T ISS SENS IN A/T ISS SENS LO IN A/T ISS SENSOR OUT ACCELERATOR PEDAL POSITION MODULE (PART OF ACCELERATOR PEDAL) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION INPUT SHAFT SPEED SENSOR (LEFT FRONT OF TRANSMISSION) BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE CLASS II DATA DK BLU WIRE DK GRN WIRE ECM-B FUSE ECT SENSOR IN ENGINE COOLANT TEMP SENSOR (NEAR THERMOSTAT HOUSING) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GROUND GRY WIRE GRY/BLK WIRE HI PPL HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN OR START UNDERHOOD FUSE/RELAY CENTER ECM 1 FUSE HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK PNK WIRE PNK WIRE POWER POWERTRAIN CONTROL MODULE (RIGHT SIDE OF DASH NEAR BLOWER MOTOR) PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID LO RED WIRE RED/BLK WIRE SENSOR GROUND STOP/HAZ FUSE 1 STOPLAMP SWITCH IN TAN WIRE TAN/WHT WIRE TCC PWM SOL TCC PWM SOLENOID TFT SENSOR IN TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANSFER CASE CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES TURN/ HAZARD SWITCH, CHIME MODULE VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR (VSS) ADAPTOR VEHICLE SPEED SENSOR BUFFER (RIGHT SIDE OF DASH) VSS HI IN VSS IN VSS LO IN VSS OUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR 999 998 961 452 389 995 PPL ACCELERATOR PEDAL POSITION (APP) MODULE (TOP OF ACCEL- ERATOR BRACKET) APP #3 APP #3 SENSOR SIG APP 1 APP 2 BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK GRN WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (LEFT LOWER FRONT OF ENGINE BLOCK) GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK IGNITION FEED 3-2 CONTROL SOL DIAGNOSTIC REQUEST WIRE PNK WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT SIDE OF DASH) PPL PPL TCC/BRAKE SW PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) STOP/HAZ FUSE 1 TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC SOL TCC/STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TRANS FUSE 20 TRANSFER CASE SWITCH TRANSMISSION UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL ACCELERATOR PEDAL POSITION (APP) MODULE (TOP OF ACCEL- ERATOR BRACKET) APP #3 APP #3 SENSOR SIG APP 1 APP 2 BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (LEFT LOWER FRONT OF ENGINE BLOCK) GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK IGNITION FEED DIAGNOSTIC REQUEST WIRE PNK WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT SIDE OF DASH) PPL PPL TCC/BRAKE SW PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) STOP/HAZ FUSE 1 TAN WIRE TCC/STOP LAMP SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) TRANS FLUID TEMP (TFT) SENSOR TRANS FUSE 20 TRANS INPUT SPD SIG LO TRANSFER CASE SWITCH TRANSMISSION TRANSMISSION INPUT SPEED SENSOR (FRONT OF TRANSMISSION) UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

ABS FUSE ABS IND. BATTERY PUMP MOTOR GROUND BLK WIRE BLK/WHT WIRE BRAKE FUSE 18 BRAKE IND BRAKE PRESSURE WARNING SWITCH (UNDERSIDE OF EBCM) BRAKE SW OUTPUT BRN WIRE DAYTIME RUNNING LAMP (DRL) MODULE (BEHIND LEFT SIDE OF DASH) DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) ENGINE CONTROLS SYSTEM FRONT AXLE ACTUATOR (ON RIGHT REAR OF FRONT DRIVE AXLE) FUSE/RELAY BLOCK (LEFT REAR OF ENGINE COMPT) GAUGES FUSE 4 HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) IGNITION ABS IND GROUND BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T NEAR BREAKOUT TO TRANSFER CASE RELAY) PNK WIRE PPL PPL DATA LINK CONNECTOR (DLC) (LEFT OF STEERING COLUMN) PPL PPL 1807 680 PPL SERIAL DATA PPL/WHT WIRE RED WIRE RIGHT FRONT WHEEL SPEED SENSOR SENSOR LOW SENSOR LOW SENSOR HIGH SENSOR HIGH 830 872 STOPLAMP SWITCH (TOP OF BRAKE PEDAL) TAN WIRE TAN/WHT WIRE TRANSFER CASE CONTROL MODULE (ON STEERING COLUMN SUPPORT BRACKET) TRANSMISSIONS SYSTEM VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (VSS) (LEFT SIDE OF TRANSMISSION/ TRANSFER CASE) VEHICLE SPEED SIG VSS VSS SIG BRAKE LAMP IND OUT SERIAL DATA LINE BRAKE IND INPUT EBCM GROUND YEL WIRE YEL/BLK WIRE

A/T ACCY BLK WIRE BULB TEST CRANK FUSE 8 DIESEL EXCEPT DIESEL (BASE) EXCEPT DIESEL (UPLEVEL) HOLD- IN COIL I/P FUSE BLOCK (LEFT SIDE OF DASH, IGN A FUSE 6 IGNITION SWITCH LEFT BATTERY (DIESEL) LOCK OFF MEGA FUSE BLOCK (RIGHT FRONT OF ENGINE COMPT, NEAR BATTERY) NCA WIRE POWER DISTRIBUTION SYSTEM PPL PPL (RIGHT FRONT WHEELHOUSE) CLUTCH PEDAL POSITION SWITCH (TOP OF CLUTCH PEDAL) PPL A/T M/T PPL PPL PULL- IN COIL RED WIRE REMOTE BATTERY STUD RIGHT BATTERY RUN WIRE STARTER MOTOR STARTER RELAY STARTER SOLENOID TRANSMISSION RANGE SWITCH (LEFT SIDE OF TRANSMISSION) WHT WIRE YEL WIRE

1000 OHMS AIR BAG FUSE 10 AIR BAG INDICATOR AUDIO ALARM MODULE BLK WIRE BLK/WHT WIRE BRN WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF DASH) DK GRN WIRE DK GRN/WHT WIRE GAUGES FUSE 4 GRN WIRE GRY WIRE HOT IN RUN, START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INFLATABLE RESTRAINT I/P MODULE INFLATABLE RESTRAINT IP MODULE SWITCH (PICK UP ONLY) INFLATABLE RESTRAINT STEERING WHEEL MODULE INFLATABLE RESTRAINT STEERING WHEEL MODULE COIL INSTRUMENT CLUSTER OFF PNK WIRE PPL/WHT WIRE SEAT BELT SWITCH (CLOSED W/SEAT BELT UNBUCKLED) (ON DRIVER'S SEAT BELT BUCKLE) SHORTING BAR SHORTING BAR DK TAN WIRE TAN/BLK WIRE W/LUXURY PACKAGE W/LUXURY PACKAGE W/O LUXURY PACKAGE W/O LUXURY PACKAGE WHT WIRE WHT/BLK WIRE YEL WIRE

11 12 PPL 2-3 SHIFT SOL CTRL 3-2 SHIFT SOL CTRL AIR PUMP REL CTRL VSS SIG BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE BRN/WHT WIRE CAM POSIT SENS SIG CAMSHAFT POSITION SENSOR (INSIDE DISTRIBUTOR) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK PNK WIRE GRN WIRE IGN SENS SENS FEED SIG RTN INLINE GENDER ADAPTER KNOCK SENS SIG LOW REF FUEL GAUGE LVL TCC SOL CTRL PPL LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE LT LT LT PPL NCA WIRE PNK IGNITION FEED WIRE PNK OTHERS WIRE PNK PNK 1 2 WIRE PNK PNK PNK PNK 3 4 5 6 7 WIRE PNK PPL WIRE PNK WIRE PNK/BLK WIRE PPL PPL PNK WIRE PPL SENSOR RETURN LOW REF VSS SIGNAL CRANK POSIT SENS SIG PPL/WHT WIRE RED/BLK WIRE SENSOR RETURN SENSOR SIGNAL TAN WIRE TAN/BLK WIRE TAN/WHT WIRE VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VENT CTLR WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL LT 2-3 SHIFT SOLENOID 3-2 SHIFT SOLENOID 6 7 8 9 10 PNK WIRE AIR INJECTION REACTION PUMP MOTOR (LEFT FRONT OF ENG COMPT) AIR INJECTION REACTION PUMP RELAY (CALIFORNIA) (UNDERHOOD FUSE/ RELAY CENTER) AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH AUX-B FUSE BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE EVAPORATIVE EMISSIONS (EVAP) CANISTER VENT VALVE (LEFT SIDE OF ENGINE COMPT) EXHAUST GAS RECIRCULATION (EGR) VALVE (FRONT OF ENGINE NEAR THERMOSTAT HOUSING) FUEL INJ 1 FUEL INJ 2 FUEL INJ 3 FUEL INJ 4 FUEL INJ 5 FUEL INJ 6 FUEL INJ 7 FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN, START LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT PNK WIRE NCA WIRE ORG/ WIRE PNK FUEL INJ 8 WIRE PNK PNK PNK 1 2 3 4 5 WIRE PNK PNK PNK PNK 3 4 5 6 7 WIRE PNK PNK PNK PNK PNK WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL LT PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RED WIRE RED/BLK WIRE SOLENOID CHECK VALVE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TCC SOLENOID TORQUE CONVERTER CLUTCH PULSE WIDTH MODULATION SOLENOID TRANS FLUID TEMPERATURE SENSOR UNDER HOOD FUSE/RELAY CENTER WHT WIRE YEL WIRE YEL/BLK WIRE