GMC Pickup K1500 (1985-1999) blk/wht Wiring diagrams

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 RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER FUSE 3 BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE GRY/BLK WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD FUSE-RELAY CENTER HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL 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 RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER FUSE 3 BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE GRY/BLK WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD FUSE-RELAY CENTER HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL 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 RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER FUSE 3 BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE GRY/BLK WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD FUSE-RELAY CENTER HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID 3-2 DOWNSHIFT SOL AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU WIRE BRAKE FUSE 18 BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DASH FUSE BLOCK DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP RIGHT FRONT OF ENGINE) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN OFF, RUN OR START HOT IN RUN HOT IN RUN OR START 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 PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL HI SOLENOID LO RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC PWM SOLENOID TCC SOL TCC SOLENOID THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANS TEMP SIG IN TRANSFER CASE CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO WHT WIRE YEL WIRE YEL/BLK WIRE

39 1807 PNK PPL WIRE BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (DLC) (UNDER LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) PPL DIESEL DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC VARIABLE ORIFICE (EVO)/ PASSLOCK MODULE (UNDER CENTER OF DASH) EVO SOLENOID OUT EVO FEED SWS POSIT SIG VSS SIGNAL INPUT GAS GAUGES FUSE 4 GROUND IGNITION DATA SENSOR RETURN 5 VOLT REF BATTERY GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) LT BLU WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE SECURITY/STRG FUSE 21 SENSOR RETURN STEERING ASSIST CONTROL SOLENOID (PART OF POWER STEERING PUMP) STEERING HANDWHEEL SPEED SENSOR (ON STEERING COLUMN, NEAR FIREWALL) STEERING VOLT WHEEL POSIT REF SIGNAL VEHICLE CONTROL MODULE (ON LEFT SIDE OF ENGINE COMPARTMENT) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS SIG OUT WHT WIRE

4.3L A/C COMPRESSOR CLUTCH A/C COMPRESSOR CYCLING SWITCH A/C HIGH PRESSURE (NOT CUTOUT USED) SWITCH AIR REACTION INJECTION (SECONDARY) WATER PUMP VALVE (7.4L ONLY) BALANCE FUEL FUEL PUMP GAGE BALANCE SENDER MODULE BLK WIRE BLK/WHT WIRE BLOWER MOTOR BRAKE PRESSURE WARNING SWITCH CRUISE INSTRUMENT CONTROL CLUSTER MODULE DATA LINK CONNECTOR DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE EVAPORATIVE EMISSIONS PURGE VACUUM SOLENOID SWITCH EXCEPT 4.3L FRONT AXLE ACTUATOR FRONT MODE DOOR MOTOR FRONT TEMPERATURE DOOR MOTOR FUEL PUMP AND SENDER GASOLINE HEATED OXYGEN SENSOR BANK 1 SENSOR 1 HEATED OXYGEN SENSOR BANK 1 SENSOR 2 HEATED OXYGEN SENSOR BANK 2 SENSOR 1 HEATED OXYGEN SENSOR BANK 2 SENSOR 2 HIGH A/C PRESSURE CUTOUT SWITCH HIGH BLOWER MOTOR RELAY IGNITION COIL MODULE MASS AIRFLOW SENSOR PARK/ NEUTRAL POSITION SWITCH POWER STEERING CONTROL MODULE RECIRCULATION DOOR MOTOR STARTER RELAY STOPLAMP RELAY TRANSFER CASE RELAY TRANSFER CASE RELAY BREAKOUT) UNDER- HOOD LAMP UNDERHOOD FUSE- RELAY CENTER A/C COMPRESSOR CLUTCH RELAY UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE VEHICLE UNDER- SPEED HOOD SENSOR REEL (BLUNT CUT) LAMP W/ DUAL TANKS W/O DUAL TANKS (EXCEPT 4.3L) UNDERHOOD FUSE- RELAY CENTER FUEL PUMP RELAY

4.3L ONLY BALANCE FUEL GAGE SENDER BENCH OTHERS SEAT BLK WIRE BLK/WHT WIRE CENTER HIGH MOUNT STOP LAMP CONVENIENCE CENTER CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DATA LINK CONNECTOR DIESEL DOOR LOCK RELAY ELECTROCHROMIC REARVIEW MIRROR W/ COMPASS FOUR-WHEEL DRIVE INDICATOR LAMP FUEL GAGE SENDER FUEL PUMP AND SENDER FUEL PUMP BALANCE MODULE INSTRUMENT CLUSTER INTERIOR LAMP CONTROL MODULE LEFT CLEARANCE LAMP LEFT FRONT POWER WINDOW LOCK SWITCH LEFT ILLUMINATED VANITY MIRROR LEFT POWER LUMBAR SUPPORT MOTOR LEFT REAR REAR POWER WINDOW WINDOW LOCKOUT SWITCH SWITCH MASS AIRFLOW SENSOR POWER AMPLIFIER POWER AMPLIFIER RELAY POWER FUEL STEERING PUMP CONTROL RELAY MODULE POWER OUTSIDE REARVIEW MIRROR SWITCH POWERTRAIN CONTROL MODULE REMOTE CONTROL DOOR LOCK RECEIVER RIGHT CLEARANCE LAMP RIGHT FRONT POWER WINDOW SWITCH RIGHT ILLUMINATED VANITY MIRROR RIGHT POWER LUMBAR SUPPORT MOTOR RIGHT POWER POWER LEFT POWER LUMBAR MOTOR SEAT RIGHT REAR POWER WINDOW SWITCH ROOF MARKER LAMPS SEAT BELT SWITCH TAN/WHT WIRE TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP UNDER HOOD FUSE-RELAY CENTER VEHICLE SPEED SENSOR BUFFER WHT/ BLK WIRE

2-HI IND 2-HI SW 4 LO INDIC CTRL 4 LO SW 4 LOW SELECT SW IN 2 HI SELECT SW IN 4 HI SELECT SW IN BATTERY IN 4-HI IND 4-HI SW 4-LO IND 5 CM FROM TRANSFER CASE RELAY BREAKOUT FROM AXLE SWITCH) 79 CM FROM ENGINE HARNESS BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CHANNEL A CHANNEL B CHANNEL C CHANNEL P DATA LINK CONNECTOR (PARTIAL) (UNDER LEFT SIDE OF DASH) DIESEL DK BLU/WHT WIRE DK GRN/WHT WIRE FRONT AXLE ACTUATOR FRONT AXLE SWITCH FRONT AXLE SWITCH (RIGHT REAR OF FRONT DRIVE AXLE) FUSE 24 GASOLINE GAUGES FUSE 4 GROUND GROUND GROUND BATTERY IN BATTERY IN PNP SWITCH OUT GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) ILLUMINATION LAMP LT BLU WIRE LT GRN WIRE ORG (OR LT GRN/BLK) WIRE ORG/ WIRE PARK/NEUTRAL POSITION SWITCH (ON LEFT SIDE, CENTER OF TRANSMISSION) PNK IGNITION IN ENCODER GROUND GROUND 2 HI INDIC CTRL 4 HI INDIC CTRL WIRE PNK WIRE POWERTRAIN CONTROL MODULE (DIESEL) PPL/WHT WIRE REAR LIFTGATE WINDOW RELEASE CIRCUIT RED WIRE RED/WHT WIRE SPARE POWER SOURCE AUXILIARY BATTERY RELAY SPARE POWER SOURCE TAN/BLK WIRE TCASE FUSE 2 TCC/STOP LAMP SWITCH (TOP OF BRAKE PEDAL) TRANS- MISSION CIRCUIT TRANSFER CASE CONTROL MODULE (STEERING COLUMN BRACKET) TRANSFER CASE ENCODER (LEFT SIDE CENTER OF TRANSFER CASE) TRANSFER CASE ENCODER MOTOR (LEFT SIDE OF TRANSFER CASE) TRANSFER CASE RELAY (1-TON VEHICLES ONLY) (RIGHT SIDE OF FIREWALL) TRANSFER CASE SELECT SWITCH TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER (TOP OF TRANSFER CASE) TURN B/U FUSE 16 TURN SIGNAL SWITCH WHT WIRE YEL WIRE YEL/BLK WIRE

2-HI IND 2-HI SW 4 LO INDIC CTRL 4 LO SW 4 LOW SELECT SW IN 2 HI SELECT SW IN 4 HI SELECT SW IN BATTERY IN 4-HI IND 4-HI SW 4-LO IND 5 CM FROM TRANSFER CASE RELAY BREAKOUT FROM AXLE SWITCH) 79 CM FROM ENGINE HARNESS BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CHANNEL A CHANNEL B CHANNEL C CHANNEL P DATA LINK CONNECTOR (PARTIAL) (UNDER LEFT SIDE OF DASH) DIESEL DK BLU/WHT WIRE DK GRN/WHT WIRE FRONT AXLE ACTUATOR FRONT AXLE SWITCH FRONT AXLE SWITCH (RIGHT REAR OF FRONT DRIVE AXLE) FUSE 24 GASOLINE GAUGES FUSE 4 GROUND GROUND GROUND BATTERY IN BATTERY IN PNP SWITCH OUT GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) ILLUMINATION LAMP LT BLU WIRE LT GRN WIRE ORG (OR LT GRN/BLK) WIRE ORG/ WIRE PARK/NEUTRAL POSITION SWITCH (ON LEFT SIDE, CENTER OF TRANSMISSION) PNK IGNITION IN ENCODER GROUND GROUND 2 HI INDIC CTRL 4 HI INDIC CTRL WIRE PNK WIRE POWERTRAIN CONTROL MODULE (DIESEL) PPL/WHT WIRE REAR LIFTGATE WINDOW RELEASE CIRCUIT RED WIRE RED/WHT WIRE SPARE POWER SOURCE AUXILIARY BATTERY RELAY SPARE POWER SOURCE TAN/BLK WIRE TCASE FUSE 2 TCC/STOP LAMP SWITCH (TOP OF BRAKE PEDAL) TRANS- MISSION CIRCUIT TRANSFER CASE CONTROL MODULE (STEERING COLUMN BRACKET) TRANSFER CASE ENCODER (LEFT SIDE CENTER OF TRANSFER CASE) TRANSFER CASE ENCODER MOTOR (LEFT SIDE OF TRANSFER CASE) TRANSFER CASE RELAY (1-TON VEHICLES ONLY) (RIGHT SIDE OF FIREWALL) TRANSFER CASE SELECT SWITCH TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER (TOP OF TRANSFER CASE) TURN B/U FUSE 16 TURN SIGNAL SWITCH WHT WIRE YEL WIRE YEL/BLK WIRE

2-HI IND 2-HI SW 4 LO INDIC CTRL 4 LO SW 4 LOW SELECT SW IN 2 HI SELECT SW IN 4 HI SELECT SW IN BATTERY IN 4-HI IND 4-HI SW 4-LO IND 5 CM FROM TRANSFER CASE RELAY BREAKOUT FROM AXLE SWITCH) 79 CM FROM ENGINE HARNESS BREAK-OUT) BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CHANNEL A CHANNEL B CHANNEL C CHANNEL P DATA LINK CONNECTOR (PARTIAL) (UNDER LEFT SIDE OF DASH) DIESEL DK BLU/WHT WIRE DK GRN/WHT WIRE FRONT AXLE ACTUATOR FRONT AXLE SWITCH FRONT AXLE SWITCH (RIGHT REAR OF FRONT DRIVE AXLE) FUSE 24 GASOLINE GAUGES FUSE 4 GROUND GROUND GROUND BATTERY IN BATTERY IN PNP SWITCH OUT GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) ILLUMINATION LAMP LT BLU WIRE LT GRN WIRE ORG (OR LT GRN/BLK) WIRE ORG/ WIRE PARK/NEUTRAL POSITION SWITCH (ON LEFT SIDE, CENTER OF TRANSMISSION) PNK IGNITION IN ENCODER GROUND GROUND 2 HI INDIC CTRL 4 HI INDIC CTRL WIRE PNK WIRE POWERTRAIN CONTROL MODULE (DIESEL) PPL/WHT WIRE REAR LIFTGATE WINDOW RELEASE CIRCUIT RED WIRE RED/WHT WIRE SPARE POWER SOURCE AUXILIARY BATTERY RELAY SPARE POWER SOURCE TAN/BLK WIRE TCASE FUSE 2 TCC/STOP LAMP SWITCH (TOP OF BRAKE PEDAL) TRANS- MISSION CIRCUIT TRANSFER CASE CONTROL MODULE (STEERING COLUMN BRACKET) TRANSFER CASE ENCODER (LEFT SIDE CENTER OF TRANSFER CASE) TRANSFER CASE ENCODER MOTOR (LEFT SIDE OF TRANSFER CASE) TRANSFER CASE RELAY (1-TON VEHICLES ONLY) (RIGHT SIDE OF FIREWALL) TRANSFER CASE SELECT SWITCH TRANSFER CASE SWITCH (TOP LEFT OF TRANSFER CASE) TRANSFER CASE SYNCHRONIZER (TOP OF TRANSFER CASE) TURN B/U FUSE 16 TURN SIGNAL SWITCH WHT WIRE YEL WIRE YEL/BLK WIRE