GMC Sierra 2500 (2000-2004) under- hood junction block Wiring diagrams

1 2 3 4 5 6 PNK WIRE 2 3 4 PPL AIR MAXI FUSE BLK WIRE BLK/WHT WIRE BRN WIRE BRN/RED WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN/WHT WIRE ECM-B FUSE ENGINE COOLANT LEVEL SWITCH (IN COOLANT RESERVOIR) ENGINE COOLANT TEMPERATURE SENSOR (LEFT FRONT OF CYLINDER HEAD) ENGINE OIL LEVEL SWITCH (RIGHT SIDE OF OIL PAN) FUEL PUMP RELAY FUEL PUMP/ LEVEL SENSOR (IN FUEL TANK) GRY WIRE HEATED OXYGEN SENSOR (BANK 1 SENSOR 1) (LEFT EXH PIPE, BEFORE CONVERTER) HEATED OXYGEN SENSOR (BANK 2 SENSOR 2) (RIGHT EXH PIPE, AFTER CONVERTER) HOT AT ALL TIMES HOT IN RUN, START IGN E FUSE KNOCK SENSOR 1 (UNDER INTAKE MANIFOLD) KNOCK SENSOR 2 (UNDER INTAKE MANIFOLD) LT BLU WIRE LT GRN WIRE NCA WIRE ORG/BLK WIRE PARK/NEUTRAL POSITION SWITCH (LEFT SIDE OF TRANSMISSION) PNK PNK WIRE PNK PPL 7 8 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 5 6 PPL PNK PNK 16 17 18 WIRE PPL PPL PPL/WHT WIRE RED WIRE SECONDARY AIR INJECTION REACTION PUMP (RIGHT REAR OF ENGINE COMPT) SECONDARY AIR INJECTION REACTION RELAY (RIGHT REAR OF ENGINE COMPARTMENT) SECONDARY AIR INJECTION REACTION SOLENOID (RIGHT REAR OF ENGINE COMPT) TAN WIRE TAN/WHT WIRE UNDER- HOOD JUNCTION BLOCK WHT WIRE WHT/ BLK WIRE YEL WIRE

28 29 30 PNK WIRE A/C REQ A/C SYSTEM AIR PUMP ANTI-LOCK BRAKE SYSTEM ANTI-LOCK BRAKE SYSTEM (SPEED SIGNAL) AUTOMATIC TRANSFER CASE CONTROL MODULE (ABOVE HEADLIGHT SWITCH) BLK WIRE BLK/ GRY WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CRUISE CONTROL SYSTEM CRUISE ENG CTRL DELIVERED TORQ PC SOL HI EGR CTRL PC SOL LO FUEL PMP RPM OUT RECIRC SW DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE EVAP VENT MIL CTRL 2-3 SS 1-2 SS VSS OUT VSS OUT TFT SENS SIG GEN F FRONT AXLE SWITCH (RIGHT SIDE OF CENTER ON AXLE HOUSING) FRT AXLE SW VSS LOW VSS HIGH FUSE FUSE BLOCK GEN L GRY WIRE GRY/BLK WIRE HOT IN RUN, START IAC COIL HI IAC COIL LO IAC COIL LO IAC COIL HI IDLE AIR CONTROL VALVE (TOP OF THROTTLE BODY) IGN IGN CTRL IGN CTRL IGN CTRL IGN CTRL IGN FEED GND EGR GND TCC SOL A/C CLU IGNITION COILS INSTRUMENT CLUSTER SYSTEMS (SPEED SIGNAL) INSTRUMENT PANEL CLUSTER MALFUNCTION INDICATOR LAMP LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE MAF SIG MAP SIG RECIRC DOOR EVAP CANP NCA WIRE PNK PNK WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT FRONT OF ENGINE COMPT) PPL PPL FUEL LEV CYC SW IN PPL PNK PNK 24 25 26 27 WIRE PPL/WHT WIRE RED WIRE RED/BLK WIRE RED/WHT WIRE REF LO REF LOW REF LOW PRND C TRANS RNG A FUEL SIG CTRL RPM OUT SENS GND SPARK PLUG SPARK PLUG SPARK PLUG STARTING/CHARGING SYSTEM TAN WIRE TAN/BLK WIRE TP SIG IAT SIG IGN CTRL IGN CTRL IGN CTRL IGN CTRL TRANSFER CASE SWITCH (LEFT FRONT OF TRANSAXLE CASE) UNDER- HOOD JUNCTION BLOCK W/ ATC WHT WIRE YEL WIRE YEL/BLK WIRE

3-2 SS SENS RTN ANTI-LOCK BRAKE SYSTEM B+ CLS 2 DATA CLS 2 DATA SENS GND REF LOW BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BELOW STEERING COLUMN) BRN WIRE BRN/RED WIRE COOLANT LEV DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ECMB FUSE ELECTRONIC SUSPENSION SYSTEM FUSE BLOCK IGN 0 FUSE FUSE FUSE GND SENS GND GRY WIRE HOT AT ALL TIMES HOT IN RUN, START INJA FUSE FUSE INJB FUSE INJECTORS KS SIGNAL KS SIGNAL CKP REQ TORQUE SERIAL DATA SERIAL DATA LIFT/DIVE SIG LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE OIL LEV ORG/ WIRE ORG/BLK WIRE PNK 1 2 3 4 5 WIRE PNK PNK WIRE PNK PPL 6 7 WIRE PNK WIRE PNK/BLK WIRE PNK/WHT WIRE POWERTRAIN CONTROL MODULE (LEFT FRONT OF ENGINE COMPT) PPL PPL PPL PPL SENS GND PPL/WHT WIRE PRND A BRK SW PRND P CLUTCH SW PPL PRND B CMP ECT SIG IGN RANGE B RANGE C IGN B+ REF LOW RED WIRE RED/BLK WIRE SENS GND SENS GND EGR INPUT TAN WIRE UNDER- HOOD JUNCTION BLOCK WHT WIRE YEL WIRE YEL/BLK WIRE

2 3 4 PPL AIR MAXI FUSE BLK WIRE BLK/WHT WIRE BRN WIRE BRN/RED WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN/WHT WIRE ECM-B FUSE ENGINE COOLANT LEVEL SWITCH (IN COOLANT RESERVOIR) ENGINE COOLANT TEMPERATURE SENSOR (LEFT FRONT OF CYLINDER HEAD) ENGINE OIL LEVEL SWITCH (RIGHT SIDE OF OIL PAN) FUEL PUMP RELAY FUEL PUMP/ LEVEL SENSOR (IN FUEL TANK) GRY WIRE HEATED OXYGEN SENSOR (BANK 2 SENSOR 2) (RIGHT EXH PIPE, AFTER CONVERTER) HOT AT ALL TIMES HOT IN RUN, START IGN E FUSE KNOCK SENSOR 1 (UNDER INTAKE MANIFOLD) LT BLU WIRE LT GRN WIRE NCA WIRE ORG/BLK WIRE PARK/NEUTRAL POSITION SWITCH (LEFT SIDE OF TRANSMISSION) PNK 1 2 3 4 5 WIRE PNK PNK WIRE PNK PPL 6 7 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 5 6 PPL PNK PNK 16 17 18 WIRE PPL PPL PPL/WHT WIRE RED WIRE SECONDARY AIR INJECTION REACTION PUMP (RIGHT REAR OF ENGINE COMPT) SECONDARY AIR INJECTION REACTION RELAY (RIGHT REAR OF ENGINE COMPARTMENT) SECONDARY AIR INJECTION REACTION SOLENOID (RIGHT REAR OF ENGINE COMPT) TAN WIRE UNDER- HOOD JUNCTION BLOCK WHT WIRE WHT/ BLK WIRE YEL WIRE

28 29 30 PNK WIRE 28 29 PNK WIRE ACCELERATOR PEDAL POSITION SENSOR (W/ ELECTRONIC THROTTLE CONTROL) ACT CNTRL APP SENS APP SENS 1 APP SENS 2 APP SENS 3 APP SENSE BLK WIRE BLK/WHT WIRE BRN WIRE CRUISE CONTROL SYSTEM CRUISE REQ DATA DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECT FUSE FUSE FUSE BLOCK GROUND GRY WIRE GRY/BLK WIRE HOT IN RUN OR START HOT IN RUN, START IAT SENSOR IGN LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MASS AIRFLOW SENSOR (IN AIR INTAKE DUCT) ORG/BLK WIRE PNK PNK 9 10 11 12 13 14 WIRE PNK WIRE PPL PPL PNK PNK 24 25 26 27 WIRE PPL PNK PNK WIRE PPL/WHT WIRE R/A INPUT RED WIRE RED/BLK WIRE S/C INPUT SENS 1 GRD SENS 1 RT SENS 2 GRD SENS 2 RT SENS 3 GRD SENS 3 RT SENS GRD SIGNAL STP LP IN TAN WIRE TAN/BLK WIRE TP SENS 1 TP SENS 2 UNDER- HOOD JUNCTION BLOCK VEH STOP FUSE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

28 29 30 PNK WIRE A/C REQ A/C SYSTEM AIR PUMP ANTI-LOCK BRAKE SYSTEM ANTI-LOCK BRAKE SYSTEM (SPEED SIGNAL) AUTOMATIC TRANSFER CASE CONTROL MODULE (ABOVE HEADLIGHT SWITCH) BLK WIRE BLK/ GRY WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CRUISE CONTROL SYSTEM CRUISE ENG CTRL DELIVERED TORQ PC SOL HI EGR CTRL PC SOL LO FUEL PMP RPM OUT RECIRC SW DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE EVAP VENT MIL CTRL 2-3 SS 1-2 SS VSS OUT VSS OUT TFT SENS SIG GEN F FRONT AXLE SWITCH (RIGHT SIDE OF CENTER ON AXLE HOUSING) FRT AXLE SW VSS LOW VSS HIGH FUSE FUSE BLOCK GEN L GRY WIRE GRY/BLK WIRE HOT IN RUN, START IAC COIL HI IAC COIL LO IAC COIL LO IAC COIL HI IDLE AIR CONTROL VALVE (TOP OF THROTTLE BODY) IGN IGN CTRL IGN CTRL IGN CTRL IGN CTRL IGN FEED GND EGR GND TCC SOL A/C CLU IGNITION COILS INSTRUMENT CLUSTER SYSTEMS (SPEED SIGNAL) INSTRUMENT PANEL CLUSTER MALFUNCTION INDICATOR LAMP LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE MAF SIG MAP SIG RECIRC DOOR EVAP CANP NCA WIRE PNK PNK WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT FRONT OF ENGINE COMPT) PPL PPL FUEL LEV CYC SW IN PPL PNK PNK 24 25 26 27 WIRE PPL/WHT WIRE RED WIRE RED/BLK WIRE RED/WHT WIRE REF LO REF LOW REF LOW PRND C TRANS RNG A FUEL SIG CTRL RPM OUT SENS GND SPARK PLUG SPARK PLUG SPARK PLUG STARTING/CHARGING SYSTEM TAN WIRE TAN/BLK WIRE TP SIG IAT SIG IGN CTRL IGN CTRL IGN CTRL IGN CTRL TRANSFER CASE SWITCH (LEFT FRONT OF TRANSAXLE CASE) UNDER- HOOD JUNCTION BLOCK W/ ATC WHT WIRE YEL WIRE YEL/BLK WIRE