GMC Forward Control P3500 (1985-1999) hot in run Wiring diagrams

1-2 SHIFT SOL 2-3 SHIFT SOL ALT FUSE BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE FUSE BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK BLU/WHT WIRE DK GRN/YEL WIRE ECM BAT FUSE ECM I FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) GRY WIRE GRY/RED WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (LEFT SIDE OF DRIVER'S ISLAND) PPL PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) TAN WIRE TCC PWM SOL TCC/BRAKE SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF TBI) TRANS FLUID TEMP (TFT) SENSOR TRANS FUSE TRANSMISSION TRANSMISSION INPUT SHAFT SPEED SENSOR (FRONT OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 SHIFT SOL 3-2 SHIFT SOLENOID A/T ISS SENS HI IN A/T ISS SENS LO IN ACCELERATOR PEDAL POSITION (APP) MODULE (THROTTLE PEDAL MOUNT) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTO TRANSMISSION INPUT SHAFT SPEED SENSOR (INSIDE FRONT OF TRANSMISSION) AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE CLASS II DATA DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM BATT FUSE ECM I FUSE ECT SENSOR IN ENGINE COOLANT TEMP SENSOR (LEFT LOWER FRONT OF ENGINE) GAUGES FUSE TRANS FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I-3 FUSE 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 WIRE POWERTRAIN CONTROL MODULE (ENGINE COMPT, TOP OF RADIATOR SUPPORT) PPL PPL DATA LINK CONNECTOR PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE SENSOR GROUND STOP/HAZ FUSE STOPLAMP SWITCH IN TFT SENSOR IN TRANS FLUID TEMP SENSOR TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR (VSS) BUFFER (ABOVE ACCELERATOR PEDAL) VSS HI IN VSS LO IN VSS OUT YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 SHIFT SOL 3-2 SHIFT SOLENOID A/C COMPRESSOR RELAY, GENERATOR, TURBO CHARGER POWER VALVE A/T INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) A/T ISS SENS HI IN A/T ISS SENS LO IN ACCELERATOR PEDAL POSITION MODULE (ATTACHED TO ACCELERATOR PEDAL) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE BUSS BAR CLASS II DATA DATA LINK CONNECTOR (PARTIAL) (BELOW DASH, NEAR STEERING COLUMN) DK BLU WIRE DK BLU/WHT WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ECM-BAT FUSE 6 ECT SENSOR IN ELECTRONIC BRAKE CONTROL MODULE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUEL PUMP RELAY, FUEL PUMP SWITCH/ENGINE OIL PRESSURE INDICATOR SENSOR GAUGES FUSE 8 GRY WIRE HAZARD LAMPS FLASHER (ABOVE STEERING COLUMN) HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I-3 FUSE 9 I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK INSTRUMENT CLUSTER WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DRIVER'S ISLAND) PPL PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE SENSOR GROUND SERVICE ENGINE SOON INDICATOR STOP-HAZ FUSE 11 STOPLAMP SWITCH IN TFT SENSOR IN TORQUE CONVERTER CLUTCH BRAKE, STOPLAMP SWITCH TRANS FLUID TEMP SENSOR TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSMISSION FUSE 17 TWISTED WIRE PAIR VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR CALIBRATOR (ABOVE ACCELERATOR PEDAL) VEHICLE SPEED SENSOR CALIBRATOR, ENGINE SHUTOFF SOLENOID VSS HI IN VSS LO IN VSS OUT YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 9 6 DATA LINK CONNECTOR BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE ECM BAT FUSE ECM I FUSE ENGINE SPEED SENSOR (TOP CENTER OF ENGINE) GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I-3 FUSE I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK RANGE SIGNAL A RANGE SIGNAL B RANGE SIGNAL C WIRE PNK WIRE PPL PPL/WHT WIRE RANGE MODE SELECTOR PRESSURE CONTROL SOLENOID RED WIRE RED/BLK WIRE SERVICE TRANSMISSION INDICATOR SYSTEM GROUND SYSTEM GROUND 452 416 SENSOR GROUND 5 VOLTS REF TAN WIRE TCC SOL 2-3 SHIFT SOL TCC/BRAKE SWITCH (BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) TRANS FUSE TRANS- MISSION TEMP SENSOR TRANSMISSION TRANSMISSION CONTROL MODULE (TCM) (LEFT SIDE OF DRIVER'S ISLAND) TRANSMISSION INPUT SHAFT SPEED SENSOR (LEFT FRONT SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR (REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER VEHICLE SPD OUTPUT VSS INPUTS WHT WIRE WHT/BLK WIRE YEL/BLK WIRE

A/C COMPRESSOR A/C HIGH PRESSURE CUTOUT SWITCH (NEAR COMPRESSOR) A/C HIGH PRESSURE CUTOUT SWITCH (ON COMPRESSOR) A/C SIGNAL BLK WIRE BLOWER MOTOR BLOWER MOTOR RESISTOR (ENGINE COMPARTMENT, ON BLOWER HOUSING) BLOWER SWITCH BRN WIRE DEF BLEND DIODE DK BLU WIRE DK GRN WIRE FUSE BLOCK FUSIBLE LINK HEAT VENT B/L HIGH BLOWER RELAY (ON EVAPORATOR HOUSING) HOT AT ALL TIMES HOT IN RUN HTR A/C FUSE LO LO HI LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE OFF MAX NORM ORG/ WIRE POWERTRAIN CONTROL MODULE (BEHIND RIGHT KICK PANEL) PPL RED WIRE SELECTOR CONTROL TAN WIRE YEL WIRE

AUXILIARY COOLING FAN AUXILIARY COOLING FAN PRESSURE SWITCH (RIGHT SIDE OF ENGINE) AUXILIARY COOLING FAN RELAY (TOP LEFT SIDE OF SHIPPING PANEL) AUXILIARY COOLING FAN TEMPERATURE SWITCH (RIGHT SIDE OF ENGINE) BLK WIRE BLK/RED WIRE DK GRN WIRE FUSE BLOCK GAUGES FUSE HOT AT ALL TIMES FUSIBLE LINK HOT IN RUN PNK/WHT WIRE RED WIRE

BLK WIRE BRN WIRE 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 FUSE BLOCK 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 HTR FUSE INSTRUMENT CLUSTER LEFT HEADLAMP ASSEMBLY 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 TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLOWER MOTOR BLOWER RESISTOR (ENGINE COMPARTMENT, ON BLOWER HOUSING) BRN WIRE FUSE BLOCK HEATER BLOWER SWITCH HOT IN RUN HTR A/C FUSE LO MED LT BLU WIRE OFF HI ORG/ WIRE YEL WIRE

85 30 PPL BLK WIRE BRAKE/ BRAKE/TRANSMISSION SHIFT INTERLOCK (BTSI) SOLENOID (ON STEERING COLUMN) BRN WIRE DIESEL DIESEL ONLY DK GRN/WHT WIRE ELECTRONIC BRAKE CONTROL MODULE (BELOW RADIATOR ON CROSSMEMBER) GASOLINE HOT IN RUN I-3 FUSE I/P FUSE BLOCK PARK/NEUTRAL POSITION AND BACKUP LAMPS SWITCH (LEFT OF TRANS) PPL TORQUE CONVERTER CLUTCH AND STOP LAMPS SWITCH (RIGHT SIDE OF STEERING COLUMN) TRANS- MISSION CONTROL MODULE (TCM) (LEFT INTERIOR FIREWALL) TURN SIGNAL FLASHER (ON FUSE BLOCK) TURN-B/U FUSE VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENG COMPT) IGN YEL WIRE

85 30 PPL BLK WIRE BRAKE/ BRAKE/TRANSMISSION SHIFT INTERLOCK (BTSI) SOLENOID (ON STEERING COLUMN) BRN WIRE DIESEL DK GRN/WHT WIRE GASOLINE HOT IN RUN I-3 FUSE I/P FUSE BLOCK PARK/ NEUTRAL POSITION SWITCH RELAY PARK/NEUTRAL POSITION, BACKUP LAMP SWITCH (LEFT OF TRANS) POWER- TRAIN CONTROL MODULE (LEFT OF DRIVER'S ISLAND) PPL TORQUE CONVERTER CLUTCH, STOP LAMPS SWITCH (REAR OF BRAKE SUPPORT BRACKET) TURN-B/U FUSE VEHICLE CONTROL MODULE (TOP OF RADIATOR SUPPORT) IGN YEL WIRE