GMC Pickup C2500 (1985-2000) ignition switch Wiring diagrams

ANTI-LOCK IND BATT GROUND BLK WIRE BRAKE IND BRAKE PRESSURE BRAKE WARN IND BROUND BRN WIRE CRUISE CONTROL SYSTEM CYLINDER DATA LINK CONNECTOR DAYTIME RUNNING LIGHTS MODULE (UNDER LEFT SIDE OF I/P) DIODE (BEHIND LEFT SIDE OF I/P) DIODE (BEHIND LEFT SIDE OF I/P) DK GRN WIRE FUSE BLOCK FUSIBLE LINK (16 GA- HOT AT ALL TIMES HOT IN RUN BRAKE FUSE HOT IN START OR RUN GAGES FUSE ECM-IGN FUSE IGN FEED ABS IND BRAKE SW IGNITION SWITCH INSTRUMENT CLUSTER LEFT FNT SENS LO RT FNT SENS LO LEFT FRONT WHEEL SENSOR LT BLU WIRE PARK BRAKE SWITCH (ON PARK BRAKE ASSEMBLY) PNK/BLK WIRE PPL PPL PPL RED WIRE RIGHT FRONT WHEEL SENSOR RT FNT SENS HI LEFT FNT SENS HI TAN WIRE TAN/WHT WIRE TCC BRAKE SWITCH (ON BRAKE PEDAL SUPPORT ARM) VSS BUFFER INPUT DLC WARNING LAMP WARNING (ON MASTER BRAKE WHT WIRE YEL WIRE

150 250 440 696 GND BLK WIRE BLU WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (BELOW MASTER CYLINDER) BRN WIRE DATA LINK CONNECTOR DAYTIME RUNNING LAMPS MODULE (UNDER LEFT SIDE OF I/P) DIODE DIODE MODULE (UNDER LEFT SIDE OF I/P) DUMP SOL FUSE BLOCK GAGES FUSE GRN WIRE HOT AT ALL TIMES HOT IN RUN BRAKE FUSE HOT IN RUN, BULB TEST OR HOT IN START OR RUN ECM-IGN FUSE IGNITION SWITCH INSTRUMENT CLUSTER ISO SOL DUMP SOL VLV RESET SOL RETURN ISOLATION ORG/ WIRE PARK BRAKE WARNING SWITCH (UNDER LEFT SIDE OF I/P) PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF INSTRUMENT PANEL) PPL REAR WHEEL ANTI-LOCK (RWAL) MODULE (LEFT REAR OF ENGINE (COMPARTMENT) RESET ANTI-LOCK BRAKE VALVE (LEFT SIDE OF ENGINE COMPARTMENT) SOL + SPD SIG INPUT WARNING LP BRAKE SW STOP FUSE TAN/WHT WIRE TCC/STOP LAMP SWITCH (TOP OF BRAKE PEDAL) VEHICLE SPEED SENSOR BUFFER (BEHIND I/P ON RIGHT SIDE OF STEERING COLUMN) WHT WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (4.3L W/ 4L60E, CALIF EMISS. ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL 23 24 PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (TOP OF BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (7.4L ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL/WHT WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) UPSHIFT LAMP WHT WIRE WHT/BLK WIRE YEL WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (4.3L W/ 4L60E, CALIF EMISS. ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL 23 24 PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (TOP OF BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

423 3 121 PNK WIRE ACCY BLK WIRE BLK/WHT WIRE BRN WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE EGR ELEC- TRONIC VACUUM REGULATOR SOLENOID (5.7L H/D ONLY) (RIGHT TOP OF ENGINE) ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF LEFT CYLINDER HEAD) FUEL PUMP AND SENDER FUEL PUMP CYCLE MODULE (5.7L H/D ONLY) FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (UNDERHOOD FUSE/RELAY CENTER) GRY WIRE HOT AT ALL TIMES IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) KNOCK SENSOR MODULE (ABOVE RIGHT SIDE ROCKER COVER) LOCK OFF LT GRN WIRE LT GRN/BLK WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE OIL PRESS IN ORG/ WIRE PNK 21 22 WIRE PNK WIRE PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE TACH IN TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) VEHICLE SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) VSS IN WHT WIRE YEL WIRE YEL/BLK WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (4.3L W/ 4L60E, CALIF EMISS. ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL 23 24 PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (TOP OF BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

423 3 121 PNK WIRE ACCY BLK WIRE BLK/WHT WIRE BRN WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE EGR ELEC- TRONIC VACUUM REGULATOR SOLENOID (5.7L H/D ONLY) (RIGHT TOP OF ENGINE) ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF LEFT CYLINDER HEAD) FUEL PUMP AND SENDER FUEL PUMP CYCLE MODULE (5.7L H/D ONLY) FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (UNDERHOOD FUSE/RELAY CENTER) GRY WIRE HOT AT ALL TIMES IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) KNOCK SENSOR MODULE (ABOVE RIGHT SIDE ROCKER COVER) LOCK OFF LT GRN WIRE LT GRN/BLK WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE OIL PRESS IN ORG/ WIRE PNK 21 22 WIRE PNK WIRE PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE TACH IN TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) VEHICLE SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) VSS IN WHT WIRE YEL WIRE YEL/BLK WIRE

423 3 121 PNK WIRE ACCY BLK WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (RIGHT TOP FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (REAR OF LEFT CYLINDER HEAD) LOCK OFF LT BLU/WHT WIRE LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (REAR TOP CENTER OF ENGINE) NCA WIRE ORG/ WIRE PNK PNK PNK 25 26 27 WIRE PNK WIRE PNK/BLK WIRE PPL PPL 1 2 3 4 PPL 22 23 PPL/WHT WIRE RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE TCC/BRAKE SWITCH (TOP OF BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (7.4L ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL/WHT WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) UPSHIFT LAMP WHT WIRE WHT/BLK WIRE YEL WIRE