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

1-3 FUSE 9 12 2 DATA LINK CONNECTOR (BELOW DASH, NEAR STEERING COLUMN) PPL ABS IND. BATTERY GROUND BLK (OR BLK/WHT) WIRE BLK WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH (INTERNAL TO ELECTRONIC BRAKE CONTROL MODULE) BRN WIRE DIESEL DIESEL: ENGINE HARN, 32 CM FROM BREAKOUT TO BATTERY JUNCTION BLOCK) DIODE NETWORK (ON I/P HARNESS, BODY BUILDER INSTALLED) DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR, ON LOWER CROSSMEMBER) FUSE LINK (IN BATTERY JUNCTION BLOCK, AT LEFT REAR OF ENGINE COMPT) GAS GAS DIESEL GAUGES FUSE 8 HOT AT ALL TIMES HOT IN RUN HOT IN RUN AND START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION ABS LAMP CONTROL BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LT BLU WIRE LT GRN WIRE NCA WIRE PNK WIRE PPL PPL PPL 1807 680 RED WIRE RIGHT FRONT WHEEL SPEED SENSOR SENSOR LOW SENSOR LOW SENSOR HIGH SENSOR HIGH 873 833 STOPLAMPS SWITCH (AT BRAKE PEDAL SUPPORT) TAN WIRE TAN/WHT WIRE VEHICLE SPEED SENSOR CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND ON RELAY BRACKET) WARNINGS SYSTEM YEL WIRE YEL/BLK WIRE

ABS IND. BLK WIRE BLK/ WHT WIRE BRAKE IND BRAKE PRESSURE DIFFERENTIAL SWITCH BRAKE/ BRN WIRE DIESEL GASOLINE DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR OF FIRST CROSSMEMBER) FUSIBLE LINK HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START GAUGES FUSE I-3 FUSE I/P FUSE BLOCK IGN ABS LAMP CONTROL BRAKE SW INPUT INSTRUMENT CLUSTER LEFT FRONT WHEEL SPEED SENSOR LFT FRT SENSOR (-) LT BLU WIRE LT GRN WIRE PNK WIRE PPL PPL PPL PUMP MOTOR POWER PUMP MOTOR GROUND RED WIRE RIGHT FRONT WHEEL SPEED SENSOR RT FRT SENSOR (-) LFT FRT SENSOR (+) RT FRT SENSOR (+) TAN WIRE TAN/WHT WIRE TCC/ STOPLAMP SWITCH UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SIG VSS BUFFER (LEFT SIDE OF INTERIOR BULKHEAD) VSS SIG SERIAL DATA LINE SERIAL DATA SIGNAL BRAKE LAMP CONTROL EBCM GROUND WHT WIRE YEL WIRE YEL/BLK WIRE

1996 VFTC ACCY BLK WIRE BLK/WHT WIRE BULB TEST DAYTIME RUNNING LAMPS (DRL) MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS (DRL) RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DAYTIME RUNNING LAMPS (DRL) RELAY 2 DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LEFT HEAD- LAMP LEFT HI BEAM HEAD- LAMP LO HI LOCK OFF LT GRN WIRE LT GRN/BLK WIRE NEAR BREAKOUT FOR CHASSIS HARNESS) ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR DRL RELAY CTRL GROUND WIRE PNK WIRE RIGHT HEAD- LAMP RIGHT HI BEAM HEAD- LAMP RUN WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE BLU WIRE BREAKOUT FOR HEADLAMP SWITCH) BULB TEST DAYTIME RUNNING LAMPS MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DAYTIME RUNNING LAMPS RELAY 2 DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR FOR LEFT HEADLAMP) FUSIBLE LINK (16 GA- GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LEFT HEAD- LAMP LEFT HIGH BEAM HEAD- LAMP LO HI LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR RELAY OUT GROUND WIRE PNK WIRE RED WIRE RIGHT HEAD- LAMP RIGHT HIGH BEAM HEAD- LAMP RUN WIRE TAN WIRE WHT WIRE YEL WIRE

BLK WIRE BLK/WHT WIRE FOR LEFT HEADLAMP) GRN WIRE HEAD PARK HEADLAMPS SWITCH HOT AT ALL TIMES INSTRUMENT CLUSTER HI BEAM INDICATOR LEFT HEAD- LAMP HI HI LO LEFT HIGH BEAM HEAD- LAMP LO HEADLAMPS DIMMER SWITCH LT GRN WIRE LT LT OFF RED WIRE RIGHT HEAD LAMP LO RIGHT HIGH BEAM HEAD- LAMP TAN WIRE YEL WIRE

1996 VFTC ACCY BLK WIRE BLK/WHT WIRE BULB TEST DAYTIME RUNNING LAMPS (DRL) MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS (DRL) RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM HI BEAM INDICATOR LEFT HEAD- LAMP LO HI LOCK OFF LT GRN WIRE LT GRN/BLK WIRE NEAR BREAKOUT FOR CHASSIS HARNESS) ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR DRL RELAY CTRL GROUND WIRE PNK WIRE RIGHT HEAD- LAMP RUN WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

4 13 PNK WIRE A/T ABS IND. ACCY BULB TEST LOCK OFF ANTI-LOCK BRAKES SYSTEM AUTO PARK IND. BLK WIRE BLK/WHT WIRE BRAKE IND DRL IND BRN/WHT WIRE CHECK GAUGES IND COOLANT TEMPERATURE GAUGE DIESEL DK BLU WIRE DK GRN WIRE DOOR AJAR IND ECM 1 FUSE 12 ENGINE CONTROLS OR STARTING/ CHARGING SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE COOLANT LEVEL SWITCH (ON LOWER LEFT END OF RADIATOR SURGE TANK) FUEL GAUGE FUEL SENDER (ON TOP OF FUEL TANK) GAS GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION SWITCH ILLUMINATION IN-LINE CONNECTOR PROVISIONS FOR BODY BUILDER INSTRUMENT CLUSTER INTERIOR LIGHTS SYSTEM WARNING SYSTEMS LEFT TURN IND LOW COOLANT IND LT BLU WIRE LT GRN (OR WHT) WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION IND. LAMP (MIL) (SERVICE ENGINE SOON IND) OIL PRESSURE GAUGE 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 VEHICLE CONTROL MODULE (ON LEFT SIDE OF RADIATOR SUPPORT) VOLTMETER VSS CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND, UNDER RELAY BRACKET) WAIT TO START IND WATER IN FUEL IND WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1223 1222 SHIFT SOL B OUT SHIFT SOL A OUT HIGH IDLE SW OUT 3-2 CTRL OUT 1225 1226 419 RANGE MODE SEL B RANGE MODE SEL C SERV ENG SOON IND CTRL 465 1229 FUEL PMP RLY CTRL FORCE MOTOR HI 470 OR 452 496 1456 KNOCK SENS INPUT EGR INPUT A/T INPUT SPEED SENSOR (ON AUTO TRANSMISSION LEFT CENTER) BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLU WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR) BRN WIRE BRN/WHT WIRE BYPASS 5 VOLTS SENS GROUND SENS GROUND TRANS TEMP INPUT DIAG ENABLE-POWERTRAIN TP SENS IN DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECT SENS INPUT EGR SOL OUT ELECTRONIC 4-SPD AUTOMATIC OVERDRIVE TRANSMISSION EVAPORATIVE CANISTER PURGE SOLENOID (TOP LEFT CENTER OF INTAKE MANIFOLD) FUEL INJ CTRL GRN WIRE GRY WIRE HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE AIR CONTROL VALVE MOTOR (ON LEFT SIDE OF THROTTLE BODY INTAKE) KNOCK SENSOR (KS) (ON RIGHT SIDE OF ENGINE BLOCK AHEAD OF STARTER) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE LT LT LT PNK PNK WIRE OIL PRESS INPUT MAP SENS INPUT ORG/ WIRE OXYGEN SENSOR (IN EXHAUST STREAM AHEAD OF MUFFLER) PCM GROUND PNK IGNITION CAN PURGE SOL OUT WIRE PNK PNK 26 27 WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (ON LEFT SIDE OF DRIVER'S ISLAND) PPL PPL 16 17 18 19 PPL 420 474 BRAKE SW INPUT PPL/WHT WIRE RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SHIFT SOL. SHIFT SOL. SHIFT SOL. SHIFT SOL. FORCE MOTOR TAN WIRE TAN/BLK WIRE TRANS FUSE TRANS TEMP WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

4 7 8 9 11 12 13 15 VSS OUT VSS RETURN GROUND BLK WIRE BLK/RED WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR, TOWARD CRUISE CONTROL MODULE) BRN WIRE BRN/WHT WIRE CONTACT CRUISE CONTROL MODULE (ON RADIATOR SUPPORT BRACKET) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM BAT FUSE ENG 1 FUSE ENGINE COOLANT TEMPERATURE SENSOR (FRONT, CENTER OF ENGINE COOLANT INTAKE) FROM BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD ENG) FROM BREAKOUT FOR GENERATOR) GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, START (CRANK) I-3 FUSE I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE SPEED CONTROL ACTUATOR (ON THROTTLE BODY) LEFT BULK- HEAD GROMMET UNDER I/P) LINEAR EGR SOLENOID VALVE (NO COMPONENT LOCATION AVAILABLE) LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK PNK 26 27 WIRE PNK WIRE PPL PPL 16 17 18 19 PPL TCC/STOPLAMP INPUT PPL/WHT WIRE RED WIRE TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (ON LEFT SIDE OF THROTTLE BODY) VEHICLE SPEED SENSOR (ON LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (ON DRIVER'S ISLAND SUPPORT ABOVE ACCELERATOR PEDAL) VSS VSS LO VSS SIG VSS HI SECOND. VSS WHT WIRE YEL WIRE

BATTERY JUNCTION BLOCK (ON FORWARD LEFT SIDE OF BULKHEAD) BLK WIRE BLK/RED WIRE BRN WIRE BRN/WHT WIRE BYPASS DIST. REF HI DIST. REF LO DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE FUEL GAUGE FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (AT RELAY CENTER RIGHT SIDE OF MAIN SUPPORT AT DRIVER'S ISLAND) FUEL PUMP, SENDER (ON TOP OF FUEL TANK) FUSIBLE LINK (16 GA- GAUGES FUSE GRY WIRE HIGH VOLTAGE IGNITION COIL WIRE HOT AT ALL TIMES HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION COIL (ON BRACKET AT REAR OF INTAKE PLENUM) IGNITION MODULE IGNITION SWITCH INSTRUMENT CLUSTER LOCK OFF OIL PRESS GAUGE ORG/ WIRE PICKUP COIL PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR SPEED METER TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE BODY FUEL INJECTOR NO.1 (ON TOP OF INTAKE MANIFOLD) THROTTLE BODY FUEL INJECTOR NO.2 (ON TOP OF INTAKE MANIFOLD) WHT WIRE