GMC Pickup K2500 (1985-2000) brn Wiring diagrams

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

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

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS HI IN A/T ISS LO IN AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE FRONT WHEEL LOCK FUEL INJECTORS, IGNITION CONTROL MOUDULE, IGNITION COIL FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH PNK WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LEFT REAR SIDE LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MAF SENSOR, HEATED OXYGEN SENSORS MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT 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 TAN WIRE TCC PWM SOL TCC PWM 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, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO YEL WIRE YEL/BLK WIRE

39 (OR 1020) AIR BAG IND ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM ANTI-THEFT SYSTEM BLK WIRE BLK/WHT WIRE BRAKE IND BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER DAYTIME RUNNING LAMPS IND DIMMING LED DK BLU WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM FUEL GAUGE FUEL PUMP/ OIL PRESSURE SWITCH, SENDER (UNDER INTAKE MANIFOLD, CENTER OF ENGINE) GENERATOR GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND IGN ILLUMINATION IND INSTRUMENT CLUSTER LOW COOLANT IND LOW COOLANT LEVEL INDICATOR MODULE (BEHIND CENTER OF DASH) LOW COOLANT LEVEL SWITCH (IN COOLANT RESERVOIR, RIGHT SIDE OF ENGINE COMPT) LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE OIL PRESS PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE PRNDL PRNDL A PRNDL B PRNDL C PRNDL PARITY RIGHT TURN IND LEFT TURN IND SAFETY BELT IND SECURITY IND SERVICE ENGINE SOON IND SERVICE THROTTLE SOON IND SOLID STATE SPEED- OMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/WHT WIRE TEMP GAUGE TRANSMISSION RANGE SWITCH (LEFT SIDE OF TRANSMISSION) VOLT- METER WAIT TO BAT IND WARNING SYSTEMS WATER IN FUEL IND WATER IN-FUEL SENSOR (ON FUEL FILTER/ MANAGER) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

A/T M/T ACCY ANTI-LOCK BRAKES SYSTEM BLK WIRE BLK/WHT WIRE BRAKE PRESSURE WARNING SWITCH (ON REAR OF EBCM CASTING) BRN WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DUAL FUEL TANKS SINGLE FUEL TANK ELECTRONIC BRAKE CONTROL MODULE (EBCM) (ON LEFT SIDE OF ENGINE COMPT) ENG-1 MINI FUSE ENGINE CONTROLS SYSTEM (FUEL PUMP BALANCE RELAY) ENGINE CONTROLS SYSTEM RADIO ENGINE CONTROLS SYSTEM FUEL GAUGE SENDER (IN FRONT FUEL TANK) FUEL PUMP BALANCE MODULE (INSIDE LEFT SIDE OF FRAME RAIL) FUEL PUMP/ SENDER GAUGES FUSE 4 GRN WIRE HOT IN RUN OR START HOT IN RUN OR START FUSE/RELAY BLOCK (LEFT REAR OF ENGINE COMPT) HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) IGN E MINI FUSE IGN SW BRAKE IND BRAKE PSI PK BRAKE 33 33 IGNITION SWITCH LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE PARK BRAKE SWITCH (ON PARK BRAKE PEDAL BRACKET) PNK 639 975 970 497 451 30 WIRE PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE RUN WIRE SECONDARY FUEL GAUGE SENDER (IN REAR FUEL TANK) TAN/WHT WIRE TRANS FUSE 20 TWISTED PAIR VEHICLE SPEED SENSOR (LEFT SIDE OF TRANSMISSION, LEFT SIDE OF TRANSFER CASE VEHICLE SPEED SENSOR (VSS) ADAPTER VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) YEL/BLK WIRE

AIR BAG IND ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM BAT IND WAIT TO BLK WIRE BLK/WHT WIRE BRAKE IND BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER DAYTIME RUNNING LAMPS IND DK BLU WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM FUEL GAUGE GENERATOR GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND IGN ILLUM ILLUMINATION IND INSTRUMENT CLUSTER LED DIMMING LEFT TURN IND RIGHT TURN IND LOW COOLANT IND LOW COOLANT LEVEL INDICATOR MODULE (BEHIND CENTER OF DASH) LOW COOLANT LEVEL SENSOR (IN COOLANT RESERVOIR, RIGHT SIDE OF ENGINE COMPT) LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE OIL PRESS OIL PRESSURE SWITCH, SENDER (UNDER INTAKE MANIFOLD, CENTER OF ENGINE) PARITY PRNDL PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE PRNDL PRNDL A PRNDL B PRNDL C SAFETY BELT IND SERVICE ENGINE SOON IND SERVICE THROTTLE SOON IND SOLID STATE SPEED- OMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/WHT WIRE TEMP GAUGE TRANSMISSION RANGE SELECTOR (LEFT SIDE OF TRANSMISSION) UP- SHIFT IND (M/T) VOLT- METER WARNING SYSTEM WATER IN FUEL IND WATER-IN FUEL SENSOR (TOP REAR OF ENGINE) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

ACCY ANTI-LOCK BRAKES SYSTEM BLK WIRE BLK/WHT WIRE BRAKE IND IN BRAKE PRESSURE WARNING SWITCH (ON REAR OF EBCM CASTING) BRN WIRE BULB TEST DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC BRAKE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) ENG-1 MINI FUSE ENGINE CONTROLS SYSTEM (FUEL PUMP BALANCE RELAY) ENGINE CONTROLS SYSTEM TRANSMISSION SYSTEM ENGINE CONTROLS SYSTEM FUEL GAGE SENDER (IN FRONT FUEL TANK) FUEL PUMP BALANCE MODULE (INSIDE LEFT SIDE OF FRAME RAIL) FUEL PUMP/ SENDER GAUGES FUSE 4 GRN WIRE HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT END OF DASH) IGN E MINI FUSE IGN SW BRAKE IND BRAKE PSI PK BRAKE 33 33 IGNITION SWITCH LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T A/T PARK BRAKE WARNING SWITCH (ON PARKING BRAKE PEDAL BRACKET) PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE RADIO RUN WIRE SECONDARY FUEL GAGE SENDER (IN REAR FUEL TANK) SINGLE FUEL TANK DUAL FUEL TANKS TAN/WHT WIRE TRANS FUSE 20 TWISTED PAIR UNDERHOOD FUSE-RELAY CENTER (LEFT REAR OF ENGINE COMPT) UNDERHOOD FUSE-RELAY CENTER (LEFT REAR OF ENGINE COMPT) DIODE 1 VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION OR TRANSFER CASE) VEHICLE SPEED SENSOR (VSS) ADAPTER VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) WHT TAN/ WIRE WHT WIRE YEL/BLK WIRE

AUDIO ALARM MODULE AUX/PWR FUSE 7 AUXILIARY POWER CONNECTOR BLK WIRE BRN WIRE CIG LTR FUSE 13 CIGAR LIGHTER CONVENIENCE CENTER CRANK FUSE 8 DATA LINK CONNECTOR DOOR REMOTE CONTROL LOCK DOOR LOCK RELAY RECEIVER FROM UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 1 OF 4) I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER LEFT FRONT DOOR LOCK SWITCH LEFT FRONT RIGHT FRONT POWER DOOR LOCK DOOR LOCK AMPLIFIER SWITCH SWITCH RELAY LEFT POWER SEAT LOCK LOCK OFF OFF LOCK OFF M/T A/T MAXI FUSE 5 MAXI FUSE 6 MAXI FUSE 7 NCA WIRE ORG/ WIRE PNK WIRE POWER WDO CIRCUIT BREAKER PPL PWR-ACCY CIRCUIT BREAKER RADIO RADIO BATT FUSE 19 RADIO FUSE 17 REAR DOOR DOOR LOCK LOCK SWITCH CONTROL MODULE REAR WINDOW LOCKOUT SWITCH (4-DR) RED WIRE REMOTE CONTROL DOOR LOCK RECEIVER RIGHT FRONT DOOR LOCK SWITCH RIGHT FRONT POWER LUMBAR SEAT SWITCH RIGHT FRONT POWER POWER WINDOW WINDOW MASTER SWITCH SWITCH (2 DR, UTILITY) RR WIPER FUSE 23 WIPER FUSE 11 RUN WIRE STARTER RELAY UNDERHOOD FUSE-RELAY CENTER STOP/HAZ FUSE 1 SUBURBAN ONLY SUBURBAN/ UTILITY PICKUP T CASE FUSE 2 TCC/STOPLAMP SWITCH TO I/P FUSE BLOCK (DIAGRAM 4 OF 4) TO SECURITY/ STRG FUSE 21 (DIAGRAM 4 OF 4) TO UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 3 OF 4) TRANS FUSE 20 TRANS- MISSION TRANSFER CASE CONTROL MODULE TURN/ HAZARD SWITCH UNDERHOOD FUSE-RELAY CENTER W/BENCH SEAT W/O BENCH SEAT WHT WIRE WINDSHIELD RADIO WIPER MOTOR MODULE YEL WIRE

AUXILIARY BATTERY AUXILIARY BATTERY RELAY (LEFT REAR OF ENGINE COMPT) AUXILIARY HEATER AND A/C CONTROL LOGIC MODULE AUXILIARY HEATER AND A/C CONTROL MODULE (FRONT) AUXILIARY HEATER AND A/C CONTROL MODULE (REAR) BLK WIRE BLK/RED WIRE BLU WIRE BRAKE FUSE 18 BRN WIRE CONVENIENCE CENTER CRUISE CONTROL MODULE CRUISE CONTROL SWITCH CRUISE FUSE 6 DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE EXCEPT DIESEL DIESEL FROM IGNITION SWITCH (DIAGRAM 2 OF 4) FROM STOP/HAZ FUSE 1 (DIAGRAM 2 OF 4) FROM UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 1 OF 4) FRONT MODE DOOR MOTOR FRONT TEMPERATURE DOOR MOTOR FUSE 24 FUSIBLE LINK GRY WIRE HEATER AND A/C CONTROL MODULE HEATER AND A/C CONTROL SWITCH HTR A/C FUSE 12 I/P FUSE BLOCK ILLUM FUSE 14 INTERIOR LIGHTS SYSTEM (HEADLAMP AND PANEL LAMP DIMMER) LEFT FRONT FENDER) ORG/ WIRE POWER STEERING CONTROL MODULE REAR AUXILIARY TEMPERATURE DOOR MOTOR REAR HIGH BLOWER RELAY REAR LOW BLOWER RELAY REAR REAR MEDIUM AUXILIARY BLOWER MODE DOOR RELAY MOTOR RECIRCULATION DOOR MOTOR RR HVAC FUSE 5 SECURITY/ STRG FUSE 21 TCC/ STOPLAMP SWITCH TRANSFER SPARE CASE POWER SELECT SOURCE SWITCH VEHICLE CONTROL MODULE

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