GMC Forward Control P3500 (1985-1999) dk blu Wiring diagrams

ABS IND. ACCY ACCY ANTI-LOCK BRAKES SYSTEM BLK WIRE BLK/WHT WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH (INTERNAL TO ELECTRONIC BRAKE CONROL MODULE) BRN/WHT WIRE CHECK GAUGES IND COOLANT TEMPERATURE GAUGE DIESEL DIODE NETWORK (DASH HARN, DK BLU WIRE DK GRN WIRE DOOR AJAR IND DRL IND ECM 1 FUSE 12 ELECTRONIC BRAKE CONTROL MODULE (EBCM) (BELOW RADIATOR, ON LOWER CROSSMEMBER) ENG 1 FUSE 15 ENGINE CONTROLS OR STARTING/CHARGING SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM TRANSMISSIONS SYSTEM ENGINE COOLANT LEVEL SWITCH (ON LOWER LEFT END OF RADIATOR SURGE TANK) FOOT BRAKE (PARK BRAKE APPLY OPPTION) FUEL GAUGE FUEL SENDER (ON TOP OF FUEL TANK) GAS GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HAND BRAKE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START I/P FUSE BLOCK I/P FUSE BLOCK (BODY BUILDER INSTALLED) I/P FUSE BLOCK) INSTRUMENT CLUSTER IGNITION SWITCH ILLUMINATION IN-LINE CONNECTOR PROVISIONS FOR BODY BUILDER INTERIOR LIGHTS SYSTEM WARNING SYSTEMS LEFT TURN IND LOCK LOCK OFF OFF LOW COOLANT IND LT BLU WIRE LT BLU/BLK WIRE LT GRN (OR WHT) WIRE LT GRN WIRE MALFUNCTION IND (MIL) (SERVICE ENGINE SOON IND) NCA WIRE OIL PRESSURE GAUGE PNK 4 13 WIRE PNK WIRE PPL PPL DIESEL PPL GAS PPL RIGHT TURN IND RUN WIRE SEAT BELT IND SERVICE THROTTLE SOON IND SPEEDOMETER TACHOMETER TAN WIRE TAN/WHT WIRE TRANS IND. VEHICLE CONTROL MODULE (ON LEFT SIDE OF RADIATOR SUPPORT) VOLTMETER VSS CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND, UNDER RELAY BRACKET) W/ DRL W/O DRL WAIT TO START IND WATER IN FUEL IND WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

0.5 WATT) 1995 VFTC BLK WIRE BLK/YEL WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (ON LEFT FRAME RAIL) IGNITION SWITCH BRAKE WARNING ALARM BUZZER (BEHIND LEFT SIDE OF I/P, NEAR FUSE BLOCK) BRN WIRE BRN/WHT WIRE COOLANT TEMP GAUGE CRUISE CONTROL SYSTEM DAYTIME RUNNING LAMPS IND DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) DAYTIME RUNNING LAMPS RELAY (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) DK BLU WIRE DK GRN WIRE DK GRN/YEL WIRE ELECTRONIC DELAY MODULE (BEHIND LEFT SIDE OF I/P, ON PARK BRAKE SUPPORT BRACKET) ENGINE CONTROLS SYSTEM FLOW SWITCH (NEAR POWER STEERING PUMP) FUEL GAUGE FUSE BLOCK GAGES FUSE GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START HYDRO-BOOST PRESSURE WARNING SWITCH (NEAR MASTER CYLINDER) ILLUM LAMP ILLUM. LAMPS IN-LINE DIODE (BEHIND LEFT SIDE OF I/P, ABOVE FUSE BLOCK) IN-LINE DIODE (BEHIND LEFT SIDE OF I/P, ABOVE STEERING COLUMN) INSTRUMENT CLUSTER LEFT TURN IND LOW COOLANT IND LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MAL- FUNCTION IND OIL PRESS GAUGE PARK BRAKE WARNING SWITCH PNK PNK WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (UNDER DRIVER'S SEAT) PPL RESISTOR RIGHT TURN IND SAFETY BELT IND SPEED- OMETER TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND LEFT SIDE OF I/P) VOLT- METER W/ DRL W/ DRL PPL PPL W/O DRL WARNING SYSTEMS WHT WIRE YEL WIRE

1995 VFTC ACCY ALT FUSE AUDIO ALARM MODULE CONVENIENCE CENTER BLK WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (NEAR MASTER CYLINDER) BRAKE WARNING ALARM BUZZER MODULE (BRAKE WARNING HARNESS) BRN WIRE BRN/WHT WIRE BULB TEST COOLANT TEMP GAUGE DAYTIME RUNNING LAMPS MODULE (TOP RIGHT SIDE OF SHIPPING HARNESS) DAYTIME RUNNING LAMPS RELAY DAYTIME RUNNING LIGHTS IND DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/YEL WIRE ELECTRONIC DELAY MODULE (BRAKE WARNING HARNESS) ENGINE CONTROLS SYSTEM ENGINE COOLANT TEMPERATURE SENDER (LEFT FRONT OF ENGINE) FLOW SWITCH (BRAKE BOOSTER) FUEL GAUGE FUEL PUMP OIL PRESSURE SWITCH, SENDER (TOP REAR OF ENGINE) FUEL PUMP, SENDER (IN FUEL TANK) FUSE BLOCK GAUGES FUSE GRY WIRE HEAD- LIGHTS SYSTEM HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START HOT IN RUN, BULB TEST OR START HYDRO-BOOST PRESSURE WARNING SWITCH (BRAKE WARNING HARNESS) I/P GROUND (AT LEFT SHIPPING PANEL) IGNITION SWITCH ILLUM. LAMPS INSTRUMENT CLUSTER LEFT TURN IND LOCK OFF LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MAL- FUNCTION IND NCA WIRE OIL PRESS GAUGE PARK BRAKE IND PARK BRAKE WARNING SWITCH (PARK BRAKE PEDAL BRACKET) PNK PPL WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF I/P, BEHIND SHIPPING PANEL) PPL RESISTOR RIGHT TURN IND. SAFETY BELT IND. RUN WIRE SHUNT SPEED- OMETER TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (LEFT SIDE OF SHIPPING PANEL) VOLT- METER W/ DRL W/O DRL WHT WIRE YEL WIRE

1995 VFTC ALT FUSE AUDIO ALARM MODULE BACKUP LAMP SWITCH (MANUAL TRANS) BACKUP LAMP SWITCH (AUTO TRANS) COLD ADVANCE FAST IDLE TEMPERATURE SWITCH WATER-IN-FUEL SENSOR CONVENIENCE CENTER DK BLU WIRE ECM CRANK FUSE FROM FUSIBLE LINK A FROM IGNITION SWITCH FUEL HEATER GENERATOR FUSE BLOCK GLOW PLUG CONTROLLER I/P CLUSTER PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE RED WIRE TCC/ BRAKE SWITCH TRANS FUSE TRANSMISSION TRANSMISSION CONTROL MODULE TURN SIGNAL FLASHER TURN-B/U FUSE VEHICLE SPEED SENSOR BUFFER WITH AUTOMATIC TRANSMISSION ONLY

ALT FUSE AUDIO ALARM MODULE BACKUP LAMP SWITCH CONVENIENCE CENTER DK BLU WIRE ECM CRANK FUSE EVAPORATIVE CANISTER PURGE SOLENOID FUSE BLOCK I/P CLUSTER IDLE SPEED CONTROL ACTUATOR IGNITION COIL IGNITION SWITCH INJ FUSE INJECTOR 1 INJECTOR 2 KNOCK SENSOR SYSTEM PNK WIRE PNK/BLK WIRE RED WIRE TCC/ BRAKE SWITCH TRANS FUSE TRANSMISSION TRANSMISSION CONTROL MODULE TURN SIGNAL FLASHER TURN-B/U FUSE VEHICLE SPEED SENSOR BUFFER VIN N W/ AUTOMATIC TRANSMISSION W/ AUTOMATIC TRANSMISSION WHT WIRE

3 121 PNK WIRE 4.3L AND 7.4L 5.7L ACCY ALT FUSE BLK WIRE BLK/RED WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUSE BLOCK GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IGNITION COIL (TOP RIGHT REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (LEFT REAR OF ENGINE, NEAR OIL PRESSURE SENDER) KNOCK SENSOR MODULE (TOP RIGHT SIDE OF ENGINE) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION (SERVICE ENGINE SOON) INDICATOR MANIFOLD ABSOLUTE PRESSURE SENSOR (ABOVE VALVE COVER) NCA WIRE ORG/ WIRE PNK 25 26 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 2 3 4 PPL 23 24 PPL/WHT WIRE PROVISIONS FOR TACHOMETER RED WIRE RED/BLK WIRE RUN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) THROTTLE POSITION SENSOR (ON THROTTLE BODY) TRANS FUSE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1 2 PPL 1-2 SHIFT SOLENIOD 2-3 SHIFT SOLENIOD 4.3L 5.7L AND 7.4L B/H CONN BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE DATA LINK CONNECTOR (BEHIND LEFT SIDE OF SHIPPING PANEL) DK BLU WIRE DK GRN/WHT WIRE ECM BAT FUSE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION FUEL PUMP AND SENDER (IN FUEL TANK) FUEL PUMP OIL PRESSURE SWITCH (TOP REAR OF ENGINE) FUEL PUMP PRIME CONNECTOR (NO LOCATION AVAILABLE) FUEL PUMP RELAY (LOWER LEFT SIDE OF SHIPPING PANEL) FUSE BLOCK GRY WIRE HEATED OXYGEN SENSOR (IN EXHAUST MANIFOLD) HOT AT ALL TIMES LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE ORG/ WIRE OXYGEN SENSOR (IN EXHAUST MANIFOLD) PNK WIRE PNK/BLK WIRE PPL PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SOLENOID TORQUE CONVERTER CLUTCH TRANS- MISSION TEMP SENSOR VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF I/P) WHT/BLK 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

3 121 PNK WIRE ACCY BLK WIRE BLK/RED WIRE BLK/YEL WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUSE BLOCK GAGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START IGNITION COIL (TOP RIGHT REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (LEFT REAR OF ENGINE, NEAR OIL PRESSURE SENDER) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION (SERVICE ENGINE SOON) INDICATOR MANIFOLD ABSOLUTE PRESSURE SENSOR (ABOVE VALVE COVER) NCA WIRE ORG/ WIRE PNK 22 23 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 20 21 PPL 3 4 PPL/WHT WIRE PROVISIONS FOR TACHOMETER RED WIRE RED/BLK WIRE RUN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (ON BRAKE PEDAL SUPPORT BRACKET) THROTTLE POSITION SENSOR (ON THROTTLE BODY) TRANS FUSE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENIOD 2-3 SHIFT SOLENIOD B/H CONN BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRN WIRE DATA LINK CONNECTOR (BEHIND LEFT SIDE OF SHIPPING PANEL) DK BLU WIRE DK GRN/WHT WIRE ELECTRONIC 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION FUEL PUMP AND SENDER (IN FUEL TANK) FUEL PUMP FUSE FUEL PUMP OIL PRESSURE SWITCH (TOP REAR OF ENGINE) FUEL PUMP PRIME CONNECTOR (TOP OF COWL) FUEL PUMP RELAY (LOWER LEFT SIDE OF SHIPPING PANEL) FUSE BLOCK GRY WIRE HOT AT ALL TIMES LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE ORG/ WIRE PNK WIRE PNK/BLK WIRE PPL PPL 3 4 PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SOLENOID TAN/BLK WIRE TORQUE CONVERTER CLUTCH TRANS- MISSION TEMP SENSOR VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF I/P) WHT/BLK WIRE YEL/BLK WIRE