GMC Pickup C2500 (1985-2000) lt blu Wiring diagrams

1-2 SHIFT SOLENOID 10 13 29 30 422 687 TCC SOL 3-2 DOWNSHIFT SOL VSS LO (GROUND) VSS HI (SIGNAL) 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CRUISE CONTROL DK BLU WIRE ECM 1 FUSE ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE ENGINE CONTROLS ENGINE COOLANT TEMPERATURE SENSOR (TOP RIGHT FRONT OF ENGINE) FLUID TEMP SENSOR FRONT WHEEL LOCK GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN HOT IN OFF, RUN OR START HOT IN RUN OR START HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) GAUGES FUSE 4 I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INLINE GENDER ADAPTOR INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP ORG/ WIRE PNK PNK WIRE PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE REV, LO RUN WIRE TAN WIRE TAN/BLK WIRE TCC PWM SOLENOID TCC SOLENOID TCC/ABS/ CRUISE SWITCH THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSFER CASE CIRCUIT TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT SIDE OF WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 10 13 29 30 422 687 TCC SOL 3-2 DOWNSHIFT SOL VSS LO (GROUND) VSS HI (SIGNAL) 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CRUISE CONTROL DK BLU WIRE ECM 1 FUSE ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE ENGINE CONTROLS ENGINE COOLANT TEMPERATURE SENSOR (TOP RIGHT FRONT OF ENGINE) FLUID TEMP SENSOR FRONT WHEEL LOCK GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN HOT IN OFF, RUN OR START HOT IN RUN OR START HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) GAUGES FUSE 4 I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INLINE GENDER ADAPTOR INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP ORG/ WIRE PNK PNK WIRE PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE REV, LO RUN WIRE TAN WIRE TAN/BLK WIRE TCC PWM SOLENOID TCC SOLENOID TCC/ABS/ CRUISE SWITCH THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSFER CASE CIRCUIT TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT SIDE OF WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID A/T ISS SENSOR VSS IN SENSOR GROUND SENSOR GROUND APP 1 SIGNAL IN ACCELERATOR PEDAL POSITION MODULE (PART OF ACCELERATOR PEDAL) APP 3 SIGNAL IN SENSOR GROUND A/T ISS SENS LO AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE PPL ENGINE CONTROLS SYSTEM ENGINE SHUTOFF SOLENOID, FUEL SOLENOID EXTERIOR LIGHTS FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HI LO HOT AT ALL TIMES HOT IN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INLINE GENDER ADAPTOR INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP ORG/ WIRE PNK PPL WIRE PNK WIRE POWERTRAIN CONTROL MODULE (RIGHT SIDE OF DASH NEAR BLOWER MOTOR) PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL PNK PNK WIRE PPL PRESS CTRL SOLENOID PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE STOP/HAZ FUSE 1 TAN WIRE TAN/WHT WIRE TCC PWM SOLENOID TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE PNK PNK REV, LO WIRE TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSFER CASE CIRCUIT TRANSFER CASE CIRCUIT PNK WIRE TURN/ HAZARD SWITCH, CHIME MODULE VEHICLE SPEED SENSOR (LEFT SIDE OF VEHICLE SPEED SENSOR BUFFER (RIGHT SIDE OF DASH) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID 29 30 VSS LO (GROUND) VSS HI (SIGNAL) ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CRUISE CONTROL DK BLU WIRE ECM 1 FUSE ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE ENGINE CONTROLS ENGINE COOLANT TEMPERATURE SENSOR (TOP RIGHT FRONT OF ENGINE) FLUID TEMP SENSOR FRONT WHEEL LOCK FUEL INJECTORS, IGNITION CONTROL MOUDULE, IGNITION COIL FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GRY WIRE GRY/BLK WIRE HI LO HOT AT ALL TIMES HOT IN HOT IN OFF, RUN OR START HOT IN RUN OR START HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DSAH) GAUGES FUSE 4 I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INLINE GENDER ADAPTOR INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP ORG/ WIRE PNK PNK WIRE PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE REV, LO RUN WIRE TAN WIRE TCC PWM SOLENOID TCC/ABS/ CRUISE SWITCH THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSFER CASE CIRCUIT TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT SIDE OF YEL WIRE YEL/BLK WIRE

BLK WIRE CIG LTR FUSE 13 CONVENIENCE CENTER (LEFT SIDE OF DASH) DOOR LOCK CONTROL MODULE (FRONT OF LEFT REAR WHEELHOUSE) DOOR LOCK RELAY (UNDER CENTER OF DASH) GROUND DOOR JAMB SW LOCK SIG UNLOCK SIG PPL GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK (LEFT SIDE OF DASH, LEFT FRONT DOOR JAMB SWITCH LEFT FRONT DOOR LOCK ACTUATOR LEFT FRONT DOOR LOCK SWITCH LEFT REAR DOOR JAMB SWITCH LEFT REAR DOOR LOCK ACTUATOR LOCK LT BLU WIRE ORG/ WIRE PPL PPL 4 DOOR PWR-ACCY CIRCUIT BREAKER REAR CARGO DOOR LOCK ACTUATOR (CARGO DOORS) REAR DOOR JAMB SWITCH REAR DOOR LOCK SWITCH (CARGO DOORS) RIGHT FRONT DOOR JAMB SWITCH RIGHT FRONT DOOR LOCK ACTUATOR RIGHT FRONT DOOR LOCK SWITCH RIGHT REAR CARGO DOOR CONTACTOR (RIGHT REAR DOOR JAMB) RIGHT REAR DOOR JAMB SWITCH RIGHT REAR DOOR LOCK ACTUATOR RR DOOR SW BATT (B+) TAN WIRE UNLOCK WHT WIRE

B+ SHOCK GRD TAMPER BLK WIRE BODY CONTROL MODULE (IN CENTER CONSOLE) CARGO DOOR JAMB SWITCH CTSY FUSE 3 DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DL BLU/WHT WIRE DOOR LOCK DOOR UNLOCK DOOR LOCK INVERSION MODULE (BEHIND LEFT SIDE OF DASH) DOOR UNLOCK DOOR LOCK GRD B+ HEADLIGHT SYSTEM HORNS SYSTEM HOT AT ALL TIMES I/P FUSE BLOCK LEFT FRONT DOOR JAMB SWITCH LEFT REAR DOOR JAMB SWITCH LIFTGATE JAMB SWITCH LT BLU WIRE LT GRN WIRE ORG/ WIRE PPL RIGHT FRONT DOOR JAMB SWITCH RIGHT REAR DOOR JAMB SWITCH SECURITY LED (IN CENTER OF FLOOR CONSOLE) SHOCK SENSOR (IN CENTER CONSOLE) TAN WIRE WHT/BLK WIRE

BLK/WHT WIRE BRN WIRE CAPACITOR DK GRN/WHT WIRE ELECTRONIC POWER STEERING SYSTEM SECURITY INDICATOR ENGINE CONTROLS SYSTEM EVO SOL FD EVO SOL OUT EVO/PASSLOCK MODULE (UNDER CENTER OF DASH) FILTER (MOLDED IN STEERING COLUMN HARNESS) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PASSLOCK SENSOR (INTERNAL TO STEERING COLUMN) PASSLOCK SENSOR REF SIGNAL GRD PNK PPL WIRE PNK WIRE PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) RED WIRE RED/WHT WIRE RESISTOR 10 OHMS SECURITY FUSE 21 STEERING HANDWHEEL SPEED SENSOR (SENSOR GROUND) WHT WIRE YEL WIRE

1-2 SHIFT SOL LT 16 17 18 PPL 2-3 SHIFT SOLENOID 3-2 SHIFT SOLENOID AIR INJECTION REACTION PUMP MOTOR (LEFT FRONT OF ENG COMPT) AIR INJECTION REACTION PUMP RELAY (CALIFORNIA) (UNDERHOOD FUSE/ RELAY CENTER) AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH AUX-B FUSE BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE EVAPORATIVE EMISSIONS (EVAP) CANISTER VENT VALVE (LEFT SIDE OF ENGINE COMPT) EXHAUST GAS RECIRCULATION (EGR) VALVE (FRONT OF ENGINE NEAR THERMOSTAT HOUSING) FUEL INJ 1 FUEL INJ 2 FUEL INJ 3 FUEL INJ 4 FUEL INJ 5 FUEL INJ 6 FUEL INJ 7 FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN, START HOT IN RUN, START UNDER HOOD FUSE/RELAY CENTER LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT PNK WIRE NCA WIRE ORG/ WIRE PNK FUEL INJ 8 WIRE PNK PNK 1 2 3 4 5 6 7 8 WIRE PNK PNK PNK 3 4 5 6 7 8 9 10 11 12 13 14 WIRE PNK PNK PNK PNK PNK WIRE PNK PNK PNK PNK WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL LT PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RED WIRE RED/BLK WIRE SOLENOID CHECK VALVE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TCC SOLENOID TORQUE CONVERTER CLUTCH PULSE WIDTH MODULATION SOLENOID TRANS FLUID TEMPERATURE SENSOR WHT WIRE YEL WIRE YEL/BLK WIRE

16 17 18 PPL 39 40 41 PPL ACTUAL GAS AF ECU BAT AF ECU GND AF ECU IGN ALTERNATIVE FUEL ENGINE CONTROL UNIT (LEFT SIDE OF ENGINE COMPT) BLK WIRE BRN WIRE BRN/WHT WIRE CLASS 2 DATA CNG FUSE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECT INPUT EGR SENS F PMP RLY FPS SIG FPS/FTS GND FTS SIG FUEL LEV OUT FUEL PRESSURE SENSOR (END OF CNG FUEL TANK) FUEL TEMPERATURE SENSOR (END OF CNG FUEL TANK) GAS FLOW OUT GAUGE SEL SW GRY WIRE HI PRES LO HOT AT ALL TIMES UNDER HOOD FUSE/RELAY CENTER HOT IN RUN, BULB TEST AND START IAT INPUT IGN E FUSE IND CTRL LOW PRES LO LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE MAF INPUT MAP INPUT MIL CTRL MIL OUT NGO ENABLE ORG/ WIRE PNK 2 3 4 5 6 7 WIRE PNK 24 25 26 27 28 29 30 31 32 33 34 35 36 37 WIRE PNK PNK PNK 3 4 5 6 7 8 9 10 11 12 13 14 WIRE PNK PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RED/BLK WIRE RELAY CTRL SENSOR GND SERIAL DATA TAN WIRE TAN/WHT WIRE TP SENSOR VSS INPUT WHT WIRE YEL WIRE YEL/BLK WIRE

32 33 PPL 39 40 41 PPL AF FUEL PUMP RELAY (LEFT OF ENGINE COMPT) BLK WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FUEL GAUGE RELAY (LEFT OF ENGINE COMPT) FUEL GAUGE SELECT SWITCH GAS MASS SENSOR (RIGHT FRONT OF ENGINE) GRY WIRE GRY/BLK WIRE HIGH PRESSURE LOCK-OFF SOLENOID (END OF CNG FUEL TANK) IGNITION RELAY (LEFT OF ENGINE COMPT) LOCK-OFF RELAY (LEFT OF ENGINE COMPT) LOW PRESSURE LOCK-OFF SOLENOID (RIGHT MIDDLE OF ENGINE) LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE MIXTURE CONTROL VALVE MOTOR (RIGHT FRONT OF ENGINE) NCA WIRE ORG/ WIRE PNK 2 3 4 5 6 7 WIRE PNK 24 25 26 27 28 29 30 31 32 33 34 35 36 37 WIRE PNK PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 WIRE PNK PNK PNK WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RED/BLK WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE YEL/BLK WIRE