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

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 PNK WIRE A/T INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) A/T ISS SENS HI IN A/T ISS SENS LO IN 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 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, 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 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, 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 BUFFER VEHICLE SPEED SENSOR BUFFER (ABOVE ACCELERATOR PEDAL) VSS HI IN VSS LO IN VSS OUT YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1223 1222 2-3 SHIFT SOL CTRL 1-2 SHIFT SOL CTRL DIAGNOSTIC TEST 1227 433 TRANS FLUID TEMP SIG BARO SENSOR INPUT 9 6 DATA LINK CONNECTOR (PARTIAL) (BELOW DASH, NEAR STEERING COLUMN) A/T INPUT SPEED SENSOR (LEFT FRONT SIDE OF TRANSMISSION) AUTOMATIC TRANSMISSION BAROMETRIC PRESSURE SENSOR (TOP LEFT REAR OF INTAKE MANIFOLD) BATTERY FEED BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DRL MODULE, DRL RELAY, GENERATOR ECM 1 FUSE 12 ECM-BAT FUSE 6 ELECTRONIC BRAKE CONTROL MODULE ENGINE OIL PRESSURE INDICATOR SENSOR, FUEL PUMP RELAY ENGINE SPEED SENSOR (IN FUEL INJECTION PUMP) ENGINE SPEED SIGNAL SENSOR GROUND TP SENSOR INPUT FUEL INJECTION PUMP SHUTOFF SOLENOID,, FUEL PUMP RELAY GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN HOT IN RUN OR START I-3 FUSE 9 I/P FUSE BLOCK IGN BUSS INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE OUT PCS HI PCS LO IGNITION PNK WIRE PNK RANGE SIGNAL A RANGE SIGNAL B RANGE SIGNAL C WIRE PNK WIRE PPL PPL BRAKE SIGNAL TCC PWM CONTROL PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RUN WIRE SERVICE TRANS OUTPUT SERIAL DATA SERVICE TRANSMISSION INDICATOR STOP LAMPS, TORQUE CONVERTER BRAKE SWITCH SYSTEM GROUND SYSTEM GROUND 452 416 SENSOR GROUND 5 VOLTS REF TAN WIRE TCC PWM SOL 2-3 SHIFT SOL THROTTLE POSITION SENSOR (ON FUEL INJECTION PUMP) TRANS FUSE 17 TRANSMISSION CONTROL MODULE (LEFT INTERIOR FIREWALL) TRANSMISSION TEMPERATURE SENSOR VEHICLE SPEED INPUT INPUT SPEED SENS LO INPUT SPEED SENS HI VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER VEHICLE SPD OUTPUT VSS INPUTS WHT WIRE WHT/BLK 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 1 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 HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (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 2 3 4 WIRE PNK PNK 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

3 4 5 PNK PNK WIRE A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (REAR OF A/C COMPRESSOR) BLK WIRE BREAKOUT) BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) FROM ECT SENSOR BREAKOUT) FUEL GAUGE FUEL SENDER, FUEL PUMP (TOP OF FUEL TANK) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION INDICATOR LAMP MAP REF LO MASS AIR FLOW SENSOR (MAF) (MOUNTED IN FRESH AIR INTAKE, BEHIND AIR FILTER BOX) NCA WIRE ORG/ WIRE PNK 6 7 8 9 10 11 12 13 14 15 WIRE PNK PNK PNK 2 3 4 5 WIRE PNK PNK WIRE PNK WIRE PPL RED WIRE RED/BLK WIRE REF LO REF THROTTLE POSITION (TP) SENSOR (ON THROTTLE BODY, TOP OF ENGINE) SENSOR BREAKOUT) SPEEDO- METER TACHO- METER TAN WIRE TEMP WHT WIRE YEL WIRE

3 4 5 PNK PNK WIRE 389 419 VSS OUTPUT MIL CTRL 420 1807 PPL PPL BRAKE SIG SERIAL DATA 440 1225 1224 IGN FEED RANGE SIG "B" RANGE SIG "A" A/C REQUEST SIG A/C SYSTEM BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRN WIRE BRN/WHT WIRE BULKHEAD GROMMET TOWARD IGNITION SW) CYLINDER 2 CYLINDER 1 CYLINDER 5 CYLINDER 3 CYLINDER 4 CYLINDER 6 DISTRIBUTOR (TOP REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-BAT FUSE 6 EGR VALVE CTRL ELECTRONIC BRAKE CONTROL MODULE FEED FUEL PUMP PRIME CONNECTOR (TAPED TO FUEL PUMP RELAY BREAKOUT) GROUND GRY WIRE HIGH VOLTAGE COIL WIRE HOT AT ALL TIMES HOT IN RUN I-3 FUSE 9 I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGN FEED IGNITION IGNITION COIL (TOP RIGHT SIDE OF ENGINE) IGNITION CONTROL MODULE (RIGHT TOP OF ENGINE, AT IGNITION COIL) LT BLU/WHT WIRE ORG/ WIRE PCS SOL (HI) INPUT SPD SENS SIG INPUT SPD SENS RTN TIMING CTRL SIG PCS SOL (LO) VCM GROUND VCM GROUND GROUND 451 451 470 PNK 6 7 8 9 10 11 12 13 14 15 WIRE PNK IGN FEED WIRE PNK WIRE PPL PPL (ENGINE HARN, 18 CM FROM BREAKOUT TO BULKHEAD CONN) PPL FUEL LEVEL PRESSURE SWITCH IN RANGE SIG "C" RED WIRE RED/ BLK WIRE RED/BLK WIRE SHIFT INTERLOCK SYSTEM PPL SPARK PLUGS TIMING CONTROL RETURN TIMING CONTROL SIGNAL) TORQUE CONVERTER CLUTCH, STOP LAMP SWITCH (AT BRAKE PEDAL SUPPPORT) TRANSMISSION INPUT SPEED SENSOR (ON LEFT SIDE OF TRNASMISSION, NEAR THE MIDDLE) WHT WIRE WHT/ BLU WIRE WHT/BLK WIRE

1-2 SHIFT SOLENOID 14 15 16 PPL PPL 2-3 SHIFT SOLENOID AUTOMATIC TRANSMISSION (A/T) (IF EQUIPPED) (REAR OF ENGINE) BLK WIRE BLU WIRE BLU/WHT WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ENG 1 FUSE 15 EXHAUST GAS RECIRCULATION (EGR) VALVE (TOP FRONT OF ENGINE) FUEL INJECTOR 1 FUEL INJECTOR 2 FUEL INJECTOR 3 FUEL INJECTOR 4 FUEL INJECTOR 5 FUEL INJECTOR 6 FUEL INJECTOR 7 FUEL INJECTOR 8 GRY WIRE HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE PNK 5 6 WIRE PNK PNK 1 2 WIRE PNK PNK 30 31 WIRE PNK PNK PNK PNK 1 2 3 4 WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL 8 9 10 11 12 13 14 15 16 17 PPL/WHT WIRE PRESSURE CONTROL SOLENOID (PCS) RED WIRE RED/BLK WIRE REV TAN WIRE TAN/WHT WIRE TCC PWM SOLENOID TRANSMISSION FLUID TEMPERATURE SENSOR TRANSMISSION RANGE (TR) PRESSURE SWITCH ASSEMBLY WHT PPL/ WIRE WHT TAN/ WIRE WHT WIRE YEL WIRE YEL/BLK WIRE

5 6 7 8 9 10 11 12 PNK PNK WIRE A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (REAR OF A/C COMPRESSOR) BLK WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) FROM ECT SENSOR BREAKOUT) FROM TP SENSOR BREAKOUT) FUEL GAUGE FUEL SENDER, FUEL PUMP (TOP OF FUEL TANK) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE MAP MASS AIR FLOW (MAF) SENSOR (MOUNTED IN FRESH AIR INTAKE, BEHIND AIR FILTER BOX) NCA WIRE ORG/ WIRE PNK 10 11 12 13 14 15 16 17 WIRE PNK 5 6 WIRE PNK PNK PNK PNK 1 2 3 4 WIRE PNK WIRE PPL PPL 1 2 PPL 8 9 RED WIRE RED/BLK WIRE REF LO REF LO TEMP REF THROTTLE POSITION (TP) SENSOR (ON THROTTLE BODY, TOP OF ENGINE) SERVICE ENGINE SOON INDICATOR SPEEDO- METER TACHO- METER TAN WIRE TRANS FUSE 17 WHT WIRE YEL WIRE

389 419 VSS OUTPUT MIL CTRL 440 1225 1224 IGN FEED RANGE SIG "B" RANGE SIG "A" 5 6 7 8 9 PNK PNK WIRE A/C REQUEST SIG A/C SW IN A/C SYSTEM BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CLUTCH PEDAL POSITION SWITCH (TOP OF CLUTCH PEDAL SUPPORT) CLUTCH SIG CYLINDER 1 CYLINDER 4 CYLINDER 5 CYLINDER 3 CYLINDER 6 CYLINDER 7 CYLINDER 2 CYLINDER 8 DISTRIBUTOR (TOP REAR OF ENGINE) DK BLU WIRE DK BLU/ WHT WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-BAT FUSE 6 EGR CTRL ELECTRONIC BRAKE CONTROL MODULE FEED IGNITION FUEL PUMP PRIME CONNECTOR (TAPED TO FUEL PUMP RELAY BREAKOUT) GROUND GRY WIRE HIGH VOLTAGE COIL WIRE HOT AT ALL TIMES HOT IN RUN I-3 FUSE 9 I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGN FEED IGNITION COIL (TOP RIGHT SIDE OF ENGINE) IGNITION CONTROL MODULE (RIGHT TOP OF ENGINE, AT IGNITION COIL) LT BLU/WHT WIRE ORG/ WIRE PCS SOL (HI) INPUT SPD SENS SIG INPUT SPD SENS RTN TIMING CTRL SIG PCS SOL (LO) VCM GND VCM GND GND 451 451 470 PNK IGN FEED WIRE PNK WIRE PPL PPL 1 2 PPL 2 4 5 16 DATA LINK CONNECTOR (DLC) (BELOW DASH, NEAR STEERING COLUMN) PPL ANTI-LOCK BRAKE SYSTEM PPL FUEL LEV PPL PPL 420 1807 BRAKE SIG SERIAL DATA RANGE SIG "C" RED WIRE RED/ BLK WIRE RED/BLK WIRE RETURN CONTROL TIMING SIGNAL CONTROL TIMING SPARK PLUGS TORQUE CONVERTER CLUTCH, STOP LAMP SWITCH (AT BRAKE PEDAL SUPPORT) TRANSMISSION INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION, NEAR THE MIDDLE) WHT WIRE WHT/BLK WIRE

1226 1225 TR SWITCH C TR SWITCH B TR SWITCH A 27 28 29 30 31 PPL A/C SYSTEM ANTILOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BATTERY BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BRN (OR LT BLU) WIRE BRN WIRE BRN/WHT WIRE CLOSURE SIGNAL BOOST SENSOR SIG PRESS CTRL SOL VLV LO DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK PNK/ PNK WIRE ECT SIGNAL GRN WIRE GRY WIRE GRY/BLK WIRE LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/WHT WIRE ORG/ WIRE ORG/BLK WIRE PNK PNK PPL 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (LEFT SIDE OF DRIVER'S ISLAND ON RELAY BRACKET) PPL PPL CKP SEN GRD A/C REQUEST SIG PPL TCC/ABS BRAKE SW STOPLAMP SWITCH CRIUSE SET/COAST SIG 20 84 PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RANGE MODE SELECTOR RED WIRE RED/BLK WIRE RESUME SENSOR GND SET- SOLENOID VALVE 1-2 SHIFT SOLENOID VALVE 2-3 SHIFT SOLENOID VALVE TCC PWM SOLID STATE SPEED CONTROL SWITCH TAN WIRE TAN/BLK WIRE TIMING STEPPER MTR (LOW) TIMING STEPPER MTR (LOW) TOWARD BREAKOUT FOR GRNERATOR CONNECTOR) TRANSMISSION OUTPUT SPEED SENSOR (LEFT SIDE OF TRANS- MISSION, NEAR THE MIDDLE) TRANSMISSION SPEED INPUT TRANSMISSION TEMPERATURE SENSOR WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

A/T A/T M/T BATTERY FEED BATTERY JUNCTION BLOCK (ON LEFT REAR OF ENG COMPT) BLK WIRE BLU WIRE BRN WIRE CRANK FUSE (UPPER RIGHT SIDE OF STEERING COLUMN SUPPORT) DK BLU WIRE ENG 1 FUSE 15 FUEL HEATER (REAR OF INTAKE MANIFOLD, PART OF FUEL/ WATER SEPARATOR) FUEL INJECTION PUMP COLD ADVANCE SOLENOID (AT FUEL INJECTION PUMP) FUSIBLE LINK FUSIBLE LINK (12 GA- FUSIBLE LINK (16 GA- FUSIBLE LINK (22 GA-RUST) FUSIBLE LINKS GLOW PLUG CONTROLLER (LEFT REAR OF ENG, NEAR FIREWALL) GLOW PLUG CTRL GLOW PLUG OUT GROUND HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IDLE SPEED CONTROL ACTUATOR SOLENOID (ON BRACKET ON FRONT FUEL INJECTION PUMP) IGN FEED IND LAMP OUT GROUND IGNITION SWITCH LEFT BANK GLOW PLUGS LOCK OFF LT GRN/BLK WIRE NOT USED STARTER FEED ORG/ WIRE PNK IGN FEED WIRE PNK WIRE PPL PPL PPL PPL S STUD RED WIRE RIGHT BANK GLOW PLUGS RUN WIRE STARTER RELAY (ON ENG FIREWALL RELAY BRACKET, UNDER BATTERY JUNCTION BLOCK) STARTER SOLENOID (ON STARTER, AT LOWER RIGHT SIDE OF ENGINE) STUD WATER IN FUEL INDICATOR SENSOR WHT WIRE YEL WIRE YEL/BLK WIRE