GMC Suburban C2500 (1985-1999) red Wiring diagrams

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR 450 450 551 413 451 417 (4.3L ONLY) BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) GAGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF DASH) PPL PPL PNK WIRE PPL/WHT WIRE RANGE MODE SELECTOR PRESSURE CONTROL SOLENOID RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TCC SOL TCC/STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF TBI) TRANS FUSE 20 TRANSMISSION UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK BLU/WHT WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) GAGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF DASH) PPL PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) TAN WIRE TCC/STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF TBI) TRANS FUSE 20 TRANSMISSION TRANSMISSION INPUT SHAFT SPEED SENSOR (FRONT OF TRANSMISSION) UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS SENS HI IN A/T ISS SENS IN A/T ISS SENS LO IN A/T ISS SENSOR OUT ACCELERATOR PEDAL POSITION MODULE (PART OF ACCELERATOR PEDAL) APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION INPUT SHAFT SPEED SENSOR (LEFT FRONT OF TRANSMISSION) BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE CLASS II DATA DK BLU WIRE DK GRN WIRE ECM-B FUSE ECT SENSOR IN ENGINE COOLANT TEMP SENSOR (NEAR THERMOSTAT HOUSING) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GROUND GRY WIRE GRY/BLK WIRE HI PPL HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN OR START UNDERHOOD FUSE/RELAY CENTER ECM 1 FUSE HOT IN RUN, BULB TEST OR START 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 PNK WIRE PNK WIRE POWER POWERTRAIN CONTROL MODULE (RIGHT SIDE OF DASH NEAR BLOWER MOTOR) PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID LO RED WIRE RED/BLK WIRE SENSOR GROUND STOP/HAZ FUSE 1 STOPLAMP SWITCH IN TAN WIRE TAN/WHT WIRE TCC PWM SOL TCC PWM SOLENOID TFT SENSOR IN TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE "A" TRANS RANGE "B" TRANS RANGE "C" TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANSFER CASE CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES TURN/ HAZARD SWITCH, CHIME MODULE VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR (VSS) ADAPTOR VEHICLE SPEED SENSOR BUFFER (RIGHT SIDE OF DASH) VSS HI IN VSS IN VSS LO IN VSS OUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE AUX FAN CTRL IGNITION A/C COMPRESSOR CLUTCH A/C COMPRESSOR CLUTCH CYCLING SWITCH (IN LOW PRESSURE LINE NEAR COMPRESSOR) A/C COMPRESSOR CLUTCH RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (AT A/C COMPRESSOR) A/C MAXI FUSE 3 CENTER A/C REQ AUX FAN MINI FUSE AUXILIARY COOLING FAN A/C PRESSURE SWITCH AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (7.4L VIN J) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLOWER MOTOR BLOWER RESISTOR (UNDER RIGHT SIDE OF I/P, ON HEATER HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE GAS DIESEL GRY WIRE GRY/BLK WIRE HEATER AND A/C CONTROL MODULE HIGH BLOWER RELAY (UNDER I/P ON TOP OF HEATER-A/C CASE) HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START IGN MINI FUSE A/C COMP MINI FUSE HOT IN RUN, BULB TEST OR START FUSE BLOCK HTR A/C FUSE 12 IGN E MINI FUSE LT BLU WIRE LT GRN WIRE NCA WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RECIRCULATION DOOR MOTOR (UNDER I/P ON HEATER- A/C CASE) RED WIRE TAN WIRE UNDERHOOD FUSE-RELAY UNDERHOOD FUSE-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL WIRE

1 2 3 4 RF (+) RF (-) LF (+) LF (-) 17 18 19 20 RR (-) RR (+) LR (-) LR (+) 5 6 7 8 9 10 GROUND PARK LAMP DIMMER ANTENNA OUT IGNITION MEMORY ANTENNA BLK WIRE BLU WIRE BRN WIRE CASSETTE DECK CTSY FUSE DK BLU WIRE DK GRN WIRE FUSE BLOCK (UNDER LEFT SIDE OF DASH) GRAPHIC EQUALIZER GROUND PARK LAMP DIMMER IGNITION MEM (DATA) DATA GRY WIRE HOT AT ALL TIMES HOT IN ACCY OR RUN LEFT FRONT SPEAKER LEFT REAR SPEAKER LT BLU WIRE LT GRN WIRE ORG/ WIRE ORG/WHT WIRE PNK WIRE POWER ANTENNA SYSTEM PPL RADIO CONTROL HEAD RADIO FUSE RADIO RECEIVER RED WIRE RED/WHT WIRE RIGHT FRONT SPEAKER RIGHT REAR SPEAKER TAN WIRE WHT WIRE YEL WIRE

1 2 3 4 RF (+) RF (-) LF (+) LF (-) 17 18 19 20 RR (-) RR (+) LR (-) LR (+) 5 6 7 8 9 10 GROUND PARK LAMP DIMMER ANTENNA OUT IGNITION MEMORY ANTENNA BLK WIRE BLU WIRE BRN WIRE CASSETTE DECK CONVENIENCE CENTER (UNDER LEFT SIDE OF DASH) CTSY FUSE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FUSE BLOCK (UNDER LEFT SIDE OF DASH) GRAPHIC EQUALIZER GROUND PARK LAMP DIMMER IGNITION MEM (DATA) DATA GRY WIRE HOT AT ALL TIMES HOT IN ACCY OR RUN INTERIOR LIGHTS SYSTEM INTERIOR LIGHTS SYSTEM LEFT FRONT SPEAKER LEFT REAR SIDE DOOR SPEAKER LEFT REAR SPEAKER LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE LT RR DOOR SPKR AMPLIFIER RELAY GROUND LT RR DOOR SPKR NOT USED LT RR SPKR LT RR SPKR RT RR DOOR SPKR NOT USED NOT USED ORG/ WIRE ORG/WHT WIRE PNK WIRE POWER AMPLIFIER RELAY (UNDER DASH, LEFT OF PEDAL BRACKET) PPL RADIO CONTROL HEAD RADIO FUSE RADIO POWER AMPLIFIER (UNDER DRIVER'S SEAT) RADIO RECEIVER RED WIRE RED/WHT WIRE RIGHT FRONT SPEAKER RIGHT REAR SIDE DOOR SPEAKER RIGHT REAR SPEAKER RT RR DOOR SPKR NOT USED NOT USED RT RR SPKR RT RR SPKR TAN WIRE WHT WIRE YEL WIRE

BLK WIRE BRN WIRE FRT WPR FUSE 11 FUSE BLOCK HOT IN ACCY OR RUN MIST NCA WIRE OFF PULSE PPL RED WIRE SOLID STATE WASH PULSE SWITCH WINDSHIELD WASHER MOTOR WIPER MOTOR MODULE WIPER/ WASHER SWITCH YEL WIRE

BLK WIRE BLU WIRE BRN WIRE CONVENIENCE CENTER (BEHIND LEFT SIDE OF I/P) CTSY FUSE 3 DOWN GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK ILLUM- NATION LAMP LEFT LEFT OUTSIDE POWER REARVIEW MIRROR LEFT/ RIGHT MOTOR LT GRN WIRE ORG/ WIRE POWER OUTSIDE REARVIEW MIRROR SWITCH PPL/WHT WIRE RED WIRE RIGHT RIGHT OUTSIDE POWER REARVIEW MIRROR UP/ DOWN MOTOR YEL WIRE

4 WHEEL DRIVE LOW (UNDER RIGHT END OF I/P) SIGNAL AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN CONTROL MODULE PPL PPL PPL RED WIRE RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE RELAY (RIGHT REAR OF ENG COMPT, NEAR BATTERY JUNCTION BLOCK) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE) TRANSFER CASE SYNCRONIZER

4 WHEEL DRIVE LOW (UNDER RIGHT END OF I/P) SIGNAL AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN CONTROL MODULE PPL PPL PPL RED WIRE RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE RELAY (RIGHT REAR OF ENG COMPT, NEAR BATTERY JUNCTION BLOCK) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE) TRANSFER CASE SYNCRONIZER