GMC Forward Control P3500 (1985-1999) tan/wht Wiring diagrams

3 2 PPL BLK WIRE DATA LINK CONNECTOR (DLC) (BELOW DASH, NEAR STEERING COLUMN) DIESEL GAS ELECTRONIC BRAKE CONTROL MODULE (EBCM) (BELOW RADIATOR, ON LOWER CROSSMEMBER) ENG BAT FUSE 10 HOT AT ALL TIMES I/P FUSE BLOCK ORG/ WIRE PPL PPL DATA CLSS 2 SERIAL DATA TAN WIRE TAN/WHT WIRE WHT/BLK WIRE

BLK WIRE BLK/WHT WIRE DATA CLSS 2 DATA LINK CONNECTOR (BELOW DASH, NEAR STEERING COLUMN) DIAG SIG DIESEL GASOLINE ELECTRONIC BRAKE CONTROL MODULE (EBCM) (BELOW RADIATOR, ON LOWER CROSSMEMBER) ENG BAT FUSE 10 HOT AT ALL TIMES I/P FUSE BLOCK ORG/ WIRE PPL PPL SERIAL DATA SERIAL DATA TAN/WHT WIRE VEHICLE CONTROL MODULE (VCM) (TOP OF RADIATOR SUPPORT)

BLK WIRE BLU WIRE BRN WIRE DAYTIME RUNNING LAMP CUTOFF RELAY DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (IN I/P HARNESS) DAYTIME RUNNING LAMPS RELAY (IN I/P HARNESS) DK BLU/WHT WIRE DK GRN/YEL WIRE GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HORN/DM FUSE HOT AT ALL TIMES HOT IN RUN OR START FUSE BLOCK HTR FUSE INSTRUMENT CLUSTER LEFT HEADLAMP ASSEMBLY LEFT LOWER HEADLAMP (W/ HPR) LT GRN WIRE LT GRN/BLK WIRE OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PROVISIONS FOR FOG LAMPS RIGHT HEADLAMP ASSEMBLY RIGHT LOWER HEADLAMP (W/ HPR) TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

ACC RADIO FUSE ACCY ACCY BULB TEST LOCK ACCY BULB TEST LOCK OFF AUTO APPLY PARK BRAKE AUX CB AUX CIRCUIT BREAKER HTR FUSE AUXILIARY COOLING FAN RELAY AUXILIARY COOLING FAN RELAY DAYTIME RUNNING LAMPS BATTERY BATTERY JUNCTION BLOCK BLK WIRE BLK/RED WIRE BRAKE WARNING ALARM BUZZER BRN WIRE BULB TEST DAYTIME RUNNING LAMPS RELAY DAYTIME RUNNING LAMPS MODULE DK GRN WIRE FROM PANEL DIMMER SWITCH ASSEMBLY (INTERIOR LIGHTS SYSTEM) FUEL PUMP RELAY FUEL PUMP OIL PRESSURE SWITCH HAZARD FLASHER FUSE BLOCK FUSIBLE FUSIBLE LINK GENERATOR GRY WIRE HEADLIGHT SWITCH HORN RELAY HORN/DM I/P CLUSTER BRAKE PRESSURE WARNING SWITCH IGNITION SWITCH INSTRUMENT CLUSTER LINK LOCK OFF LPS BUS GAGES FUSE INSTR-LPS FUSE OFF ORG/ WIRE PARK BRAKE WARNING SWITCH PCM PNK WIRE PNK/ WHT WIRE PNK/BLK WIRE PNK/WHT WIRE POWERTRAIN CONTROL MODULE PPL PWR ECM-BAT CIRCUIT BREAKER FUSE RED WIRE RELAY RUN WIRE SHUNT STARTER MOTOR STOP- HZ FUSE STOPLAMP SWITCH TAIL LPS FUSE FUSE TAN/WHT WIRE TO ALT, ECM-CRNK, TURN-B/U, TRANS, INJ FUSES AND IGNITION COIL TRANSMISSION POSITION INDICATOR LAMP WHT WIRE WINDSHIELD WIPER MOTOR WIPER SWITCH MODULE WIPER FUSE YEL WIRE

ACCY ACCY BULB TEST LOCK AUDIO ALARM MODULE AUTO APPLY PARK BRAKE AUX AUX CIRCUIT BREAKER AUXILIARY COOLING FAN RELAY BATTERY BATTERY JUNCTION BLOCK BLK WIRE BLK/RED WIRE BRAKE PRESSURE WARNING SWITCH BRN WIRE BRN/WHT WIRE BULB TEST DAYTIME RUNNING LAMPS AUXILIARY COOLING FAN RELAY DAYTIME RUNNING LAMPS MODULE DAYTIME RUNNING LAMPS RELAY DK GRN WIRE DOME LAMP ECM-BAT FUSE ACC-RADIO FUSE FROM PANEL DIMMER SWITCH ASSEMBLY (INTERIOR LIGHTS SYSTEM) FUEL PUMP OIL PRESSURE SWITCH FUEL PUMP RELAY POWERTRAIN CONTROL MODULE FUSE BLOCK FUSIBLE FUSIBLE LINK GAGES FUSE GENERATOR GRY WIRE HAZARD FLASHER HEADLIGHT SWITCH ASSEMBLY HORN RELAY HTR FUSE I/P CLUSTER IGNITION SWITCH INSTR-LPS LPS BUS FUSE LINK LOCK LOCK OFF OFF ORG/ WIRE PARK BRAKE WARNING SWITCH PCM PNK WIRE PNK/ WHT WIRE PPL PWR CIRCUIT BREAKER RED WIRE RELAY RUN WIRE SHUNT STARTER MOTOR STOP- HZ FUSE STOPLAMP SWITCH TAIL LPS FUSE HORN/DM FUSE TAN/WHT WIRE TO ALT, ECM-CRANK, TURN-B/U, TRANS, INJECTOR FUSES AND IGNITION COIL TRANSMISSION INSTRUMENT AUDIO POSITION CLUSTER ALARM INDICATOR MODULE LAMP WHT PNK/ WIRE WHT WIRE WIPER FUSE WIPER SWITCH

2-3 SHIFT SOL CTRL ANTI-LOCK BRAKE SYSTEM BLK LT GRN/ WIRE BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CAM POSIT SENS RTN FUEL LEV PPL CAMSHAFT POSITION (CMP) SENSOR (IN DISTRIBUTOR) DK BLU WIRE DK GRN WIRE DK GRN/ WHT WIRE DK GRN/WHT WIRE FEED IGN GRY WIRE HALL EFFECT SENSOR KNOCK SENS SIG KNOCK SENSOR (KS) (REAR OF ENGINE, TOP CENTER) LT BLU/ BLK WIRE LT BLU/ WHT WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WHT/ WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE NCA WIRE PNK PNK PNK 3 4 5 WIRE PNK PPL 1 2 WIRE PNK WIRE PNK/BLK WIRE PPL PPL CKP SENS RTN VSS RTN VSS SIG PPL/WHT WIRE PURGE VENT CTRL RETURN SENSOR CKP SIGNAL SENSOR CKP SYSTEM GROUND TAN WIRE TAN/WHT WIRE TANK PRESSURE SENSOR (TOP OF FUEL TANK) VEHICLE CONTROL MODULE (VCM) (ON LEFT SIDE OF ENGINE COMPARTMENT) VEHICLE SPEED OUT VEHICLE SPEED SENSOR (VSS) (LEFT REAR OF TRANSMISSION, NEAR CENTER) WHL SPD SIG, LEFT FRT CAM POSIT SENS SIG POWER WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID AUTOMATIC TRANSMISSION (A/T) (IF EQUIPPED) (REAR OF ENGINE) BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK GRN/WHT WIRE ECM 2 FUSE 12 ENG 1 FUSE 15 FUEL INJECTOR NO.2 FUEL INJECTOR NO.1 FUEL INJECTOR NO.3 FUEL INJECTOR NO.4 FUEL INJECTOR NO.5 FUEL INJECTOR NO.6 GRY WIRE HEATED OXYGEN SENSOR, BANK 1 SENSOR 2 (EXHAUST PIPE BEHIND CATALYTIC CONVERTER) HOT IN RUN, START I/P FUSE BLOCK (DASH PANEL PROVIDED BY BODY BUILDER) (BODY BUILDER INSTALLED) LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE PNK PNK PNK 2 3 4 5 WIRE PNK PNK PNK 3 4 5 WIRE PNK PNK PNK WIRE PNK PNK WIRE PNK PPL 1 2 WIRE PNK WIRE PNK/BLK WIRE PPL PPL/WHT WIRE PRESSURE CONTROL SOLENOID (PCS) RED WIRE RED/BLK WIRE REV TAN WIRE TAN/WHT WIRE TCC PWM SOLENOID TRANS FUSE 17 TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR TRANSMISSION RANGE (TR) PRESSURE SWITCH ASSEMBLY WHT WIRE YEL WIRE YEL/BLK WIRE

BLK WIRE BLK/RED WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BEHIND LEFT SIDE OF SHIPPING PANEL) DIAGNOSIS TEST TP SIGNAL INJECTOR 1 CTRL DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM BAT FUSE ECM-CRNK FUSE ECT SIGNAL EGR CONTROL ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) ENGINE GROUND FUEL PUMP RELAY CTRL FUEL PUMP SIGNAL MAP SIGNAL FUSE BLOCK GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IC BYPASS TP/ECT GROUND MAP GROUND IC SIGNAL VSS SIGNAL VSS TP REFERENCE IDLE AIR CONTROL ACTUATOR (TOP REAR OF ENGINE) INJ FUSE KNOCK SENSOR SIGNAL LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (TOP REAR OF ENGINE) MAP REFERENCE IGNITION FUSED BATTERY FEED ORG/ WIRE ORG/BLK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PPL 3 4 PPL/WHT WIRE RED WIRE SERIAL DATA TAN WIRE TAN/BLK WIRE TAN/WHT WIRE THROTTLE BODY FUEL INJECTOR #1 (TOP OF THROTTLE BODY UNIT) THROTTLE BODY FUEL INJECTOR #2 (TOP OF THROTTLE BODY UNIT) THROTTLE POSITION SENSOR (TOP RIGHT SIDE OF ENGINE) WHT WIRE WHT/BLK WIRE YEL WIRE

5.7L 7.4L 7.4L ONLY AIR CONDITION- ING SYSTEM BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE DIAGNOSTIC TEST TP SENSOR SIGNAL INJECTOR 1 CONTROL DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK GRN/YEL WIRE ECM BAT FUSE ECM I FUSE ECT SIGNAL EGR CONTROL EVAPORATIVE CANISTER PURGE CONTROL SOLENOID (TOP RIGHT SIDE OF ENGINE) EXHAUST GAS RECIRCULATION VALVE SOLENOID (TOP RIGHT SIDE OF ENGINE) FUEL PUMP RELAY CTRL PCS LOW FUEL PUMP SIGNAL MAP SIGNAL FUSE BLOCK GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IC BYPASS SENSOR GROUND SENSOR GROUND TFT SIGNAL 470 455 PPL IDLE AIR CONTROL ACTUATOR (TOP REAR OF ENGINE) IDLE SPEED ACTUATOR CONTROL SOLENOID (NO LOCATION AVAILABLE) KNOCK SIGNAL EGR PINTLE POSITION SIGNAL LINEAR EGR VACUUM REGULATOR SOLENOID VALVE (TOP FRONT OF ENGINE) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE NCA WIRE ORG/ WIRE OXYGEN SENSOR (IN EXHAUST MANIFOLD) OXYGEN SENSOR GROUND PNK 22 23 WIRE PNK RANGE SIGNAL A INPUT SPEED SIGNAL HIGH INPUT SPEED SIGNAL LOW WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PPL 20 21 PPL/WHT WIRE RANGE SIGNAL B RANGE SIGNAL C MIL CONTROL RED WIRE RED/BLK WIRE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE THROTTLE BODY FUEL INJECTOR #1 (TOP OF THROTTLE BODY UNIT) THROTTLE BODY FUEL INJECTOR #2 (TOP OF THROTTLE BODY UNIT) TRANSMISSION INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

5.7L 7.4L 7.4L ONLY AIR CONDITION- ING SYSTEM BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE DIAGNOSTIC TEST TP SENSOR SIGNAL INJECTOR 1 CONTROL DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK GRN/YEL WIRE ECM BAT FUSE ECM I FUSE ECT SIGNAL EGR CONTROL EVAPORATIVE CANISTER PURGE CONTROL SOLENOID (TOP RIGHT SIDE OF ENGINE) EXHAUST GAS RECIRCULATION VALVE SOLENOID (TOP RIGHT SIDE OF ENGINE) FUEL PUMP RELAY CTRL PCS LOW FUEL PUMP SIGNAL MAP SIGNAL FUSE BLOCK GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IC BYPASS SENSOR GROUND SENSOR GROUND TFT SIGNAL 470 455 PPL IDLE AIR CONTROL ACTUATOR (TOP REAR OF ENGINE) IDLE SPEED ACTUATOR CONTROL SOLENOID (NO LOCATION AVAILABLE) KNOCK SIGNAL EGR PINTLE POSITION SIGNAL LINEAR EGR VACUUM REGULATOR SOLENOID VALVE (TOP FRONT OF ENGINE) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE NCA WIRE ORG/ WIRE OXYGEN SENSOR (IN EXHAUST MANIFOLD) OXYGEN SENSOR GROUND PNK 22 23 WIRE PNK RANGE SIGNAL A INPUT SPEED SIGNAL HIGH INPUT SPEED SIGNAL LOW WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF SHIPPING PANEL) PPL PPL 20 21 PPL/WHT WIRE RANGE SIGNAL B RANGE SIGNAL C MIL CONTROL RED WIRE RED/BLK WIRE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE THROTTLE BODY FUEL INJECTOR #1 (TOP OF THROTTLE BODY UNIT) THROTTLE BODY FUEL INJECTOR #2 (TOP OF THROTTLE BODY UNIT) TRANSMISSION INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE