Chevrolet Chevy Express G2500 (1996-2012) tow/haul switch Wiring diagrams

1-2 SHIFT SOLENOID VALVE 2-3 SHIFT SOLENOID VALVE 27 28 GMLAN (-) GMLAN (+) 68 71 1 MIL CTRL TOS SIG ACTUATOR SIG AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LOWER RIGHT SIDE OF DASH) BRN WIRE BRN/WHT WIRE CLASS 2 CLASS 2 DATA COMPUTER DATA LINES SYSTEM DK BLU WIRE DK GRN WIRE ENGINE CONTROL MODULE (ECM) (LEFT SIDE OF ENGINE COMPT) FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH GRY WIRE IGN IGN LOGIC INSTRUMENT PANEL CLUSTER (IPC) LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PPL RED WIRE REV TAN WIRE TAN/BLK WIRE TORQUE CONVERTER CLUTCH (TCC) PULSE WIDTH MODULATION (PWM) SOLENOID VALVE TOW/ HAUL IND CLASS 2 TOW/HAUL SW TOW/HAUL SWITCH YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID VALVE 2-3 SHIFT SOLENOID VALVE 27 28 GMLAN (-) GMLAN (+) 68 71 1 MIL CTRL TOS SIG ACTUATOR SIG AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LOWER RIGHT SIDE OF DASH) BRN WIRE BRN/WHT WIRE CLASS 2 CLASS 2 DATA COMPUTER DATA LINES SYSTEM DK BLU WIRE DK GRN WIRE ENGINE CONTROL MODULE (ECM) (LEFT SIDE OF ENGINE COMPT) FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH GRY WIRE IGN IGN LOGIC INSTRUMENT PANEL CLUSTER (IPC) LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PPL RED WIRE REV TAN WIRE TAN/BLK WIRE TORQUE CONVERTER CLUTCH (TCC) PULSE WIDTH MODULATION (PWM) SOLENOID VALVE TOW/ HAUL IND CLASS 2 TOW/HAUL SW TOW/HAUL SWITCH YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID VALVE 2-3 SHIFT SOLENOID VALVE 30 45 39 MIL CTRL TOS SIG 44 57 GMLAN (-) GMLAN (+) ACTUATOR SIG AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LOWER RIGHT SIDE OF DASH) BRN WIRE BRN/WHT WIRE CLASS 2 CLASS 2 DATA COMPUTER DATA LINES SYSTEM DK BLU WIRE DK GRN WIRE ENGINE CONTROL MODULE (ECM) FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH GRY WIRE IGN INSTRUMENT PANEL CLUSTER (IPC) LOGIC LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PPL PRESSURE CONTROL (PC) SOLENOID VALVE RED WIRE REV TAN WIRE TAN YEL/BLK WIRE TAN/BLK WIRE TORQUE CONVERTER CLUTCH (TCC) PULSE WIDTH MODULATION (PWM) SOLENOID VALVE TOW/ HAUL IND CLASS 2 TOW/HAUL SW TOW/HAUL SWITCH YEL WIRE YEL/BLK WIRE

1 2 6 8 20 21 22 23 24 40 42 47 48 51 62 63 GND TCC PWM CTRL PC SOL HI CTRL 1 8 17 18 19 20 24 27 GND AUTOMATIC TRANSMISSION INPUT SHAFT SPEED SENSOR BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ENGINE COOLANT TEMPERATURE SENSOR (ON LEFT SIDE OF ENGINE) FROM UNDERHOOD PASS- THROUGH GROMMET BREAKOUT) LT GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN ACCY, RUN, START HOT IN RUN, START IGN 0 FUSE 6 INSTRUMENT PANEL CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE ORG/ WIRE ORG/BLK WIRE PC SOL LO CTRL PPL FRONT LOW SIG FRONT HIGH SIG PCM BATT FUSE 2 PCM IGN 1 FUSE 38 PNK WIRE POWERTRAIN CONTROL MODULE (IN ENGINE COMPT, ON LEFT INNER FENDER) PPL PRNDL INDICATOR RANGE B RANGE C IGN B+ GND GND RED/WHT WIRE SERIAL DATA TAN WIRE TAN/BLK WIRE TAN/WHT WIRE THROTTLE POSITION SENSOR (ON LEFT SIDE OF THROTTLE BODY) TOW/ HAUL SWITCH TOW/HAUL INDICATOR TOW/HAUL SWITCH UNDER- HOOD FUSE BLOCK VEHICLE SPEED SENSOR WHT WIRE YEL WIRE YEL/BLK WIRE

11 12 IPL DIMMER SW SIG IP DIMMING VOLT REF 2 15 HEAD 8 17 PARK LAMPS SIG HEADLAMPS OFF SIG AUXILIARY BLOWER MOTOR SWITCH BCM 1 FUSE 59 BCM 2 FUSE 58 BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LOWER RIGHT SIDE OF DASH) BODY FUSE BLOCK (UNDER LEFT FRONT SEAT) BRN WIRE BRN/WHT WIRE COMPUTER DATA LINES SYSTEM CONNECTOR) PNK WIRE CONTROL DK GRN WIRE DRIVER DOOR LOCK SWITCH DRIVER INFORMATION CENTER (DIC) SWITCH DRIVER WINDOW SWITCH FRONT AUXILIARY HVAC CONTROL ASSEMBLY HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES UNDERHOOD FUSE BLOCK (ON LEFT SIDE OF ENGINE COMPT) HVAC CONTROL ASSEMBLY IN FRONT HEADLINER HARNESS, 21 CM INFLATABLE RESTRAINT I/P MODULE DISABLE SWITCH (W/ MANUAL SUPPRESSION) IPL DIMMING CTRL LEFT STEERING WHEEL CONTROL SWITCH LT BLU WIRE OFF AUTO PARK ORG/WHT WIRE PASSENGER DOOR LOCK SWITCH PASSENGER WINDOW SWITCH PNK CONTROL PNK WIRE PNK PNK W/O REDUNDANT RADIO STEERING WHEEL WIRE PNK WIRE RADIO REAR AUXILIARY HVAC CONTROL ASSEMBLY SPLICE BLOCK RED WIRE RED/WHT WIRE RIGHT STEERING WHEEL CONTROL SWITCH SPLICE BLOCK STR/WHL/ SNSR TAN WIRE TAN/BLK WIRE TOW/HAUL SWITCH TRACTION CONTROL SWITCH (TCS) (W/ ACTIVE BRAKE CONTROL) W/ AUTOMATIC ELECTRONIC CRUISE CONTROL W/ AUXILIARY HEATER W/O REAR A/C W/ ELECTRIC SIDE DOOR LOCK W/ POWER OPERATED WINDOW (W/ POWER MIRRORS, POWER WINDOWS) W/ REAR W/O REAR AUXILIARY AUXILIARY CONTROLS CONTROLS W/ REDUNDANT RADIO STEERING WHEEL W/ RV UPFITTER W/O RADIO PROVISIONS W/O RV UPFITTER WHT WIRE YEL WIRE

1 2 B+ GND 6 7 8 9 10 11 12 BRAKE SW SIG AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR BLK/WHT WIRE BRK SW FUSE 13 BRN/WHT WIRE COMPUTER DATA LINES SYSTEM CONTROL SOLENOID VALVE ASSEMBLY DK BLU WIRE DK GRN WIRE DRIVER INFORMATION CENTER DISPLAY (DIC) ENGINE CONTROL MODULE (ECM) (LEFT SIDE OF ENGINE COMPT) EXCEPT 6.6L 6.6L EXTERIOR LIGHTS SYSTEM 1786 2501 2500 6399 GMLAN HOT AT ALL TIMES HOT W/ RUN/CRNK RELAY 15 ENERGIZED IGN IGN VOLTAGE INSTRUMENT PANEL CLUSTER INSTRUMENT PANEL CLUSTER (IPC) LOGIC LOW REFERENCE LT BLU WIRE LT BLU/WHT WIRE ORG/BLK WIRE PC SOLENOID 1 CONTROL PC SOLENOID 2 CONTROL PC SOLENOID 3 CONTROL PC SOLENOID 4 CONTROL PC SOLENOID 5 CONTROL PNK WIRE PRESSURE CONTROL (PC) SOLENOID VALVE 1 PRESSURE CONTROL (PC) SOLENOID VALVE 2 PRESSURE CONTROL (PC) SOLENOID VALVE 3 PRESSURE CONTROL (PC) SOLENOID VALVE 4 PRESSURE CONTROL (PC) SOLENOID VALVE 5 RED/WHT WIRE SHIFT SOLENOID (SS) 1 CONTROL SHIFT SOLENOID (SS) 2 CONTROL SHIFT SOLENOID (SS) VALVE 1 SHIFT SOLENOID (SS) VALVE 2 STOP LAMP SWITCH (BEHIND LEFT SIDE OF DASH, ABOVE BRAKE PEDAL) TAN WIRE TAN/BLK WIRE TCM BATT FUSE 32 TCM IGN FUSE 31 TO AUTOMATIC TRANSMISSION (DIAGRAM 2 OF 2) TORQUE CONVERTER CLUTCH (TCC) PRESSURE CONTROL (PC) SOLENOID VALVE TORQUE CONVERTER CLUTCH PRESSURE CONTROL SOLENOID CONTROL TOW/HAUL IND TOW/HAUL SWITCH TRANSMISSION CONTROL MODULE (TCM) TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR SIGNAL UNDERHOOD FUSE BLOCK (ON LEFT SIDE OF ENGINE COMPT)