GM Service Manual Online
For 1990-2009 cars only
Figure 1:

Fuse Voltage Supply


Object Number: 778396  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Air Suspension Dump Lamp, Speedometer, Voltmeter
IP Fuse Block, Curcuit Breaker 6, Page 1 of 2
Air Suspension Dump Lamp, Speedometer, Voltmeter
Illumination, Seat Belt, Primary Brake, ABS, and Park Brake Lamps
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Exhaust Brake, Air Suspension Dump Lamps and Tachometer (LG4)
Fuel, Temperature, Oil Pressure and Check Gages
Air Suspension Dump Lamp, Speedometer, Voltmeter
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Figure 2:

Air Susp Dump Lamp, Speedometer and Volt Meter


Object Number: 778403  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Illumination, Seat Belt, Primary Brake, ABS, and Park Brake Lamps
Fuse Voltage Supply
Air Suspension Dump Switch and Valve Solenoid
Fuse Voltage Supply
Fuse Voltage Supply
Splice Pack 2
Instrument Panel Lighting
Instrument Panel Lighting
G105, Splice Pack 5, S338
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361
Figure 3:

Illumination, Seat Belt, Primary Brake, ABS and Park Brake Lamps


Object Number: 778408  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Air Suspension Dump Lamp, Speedometer, Voltmeter
Fuse Voltage Supply
Aux Brake, Apply Park Brake, RH Turn, LH Turn, Service Parke Brake Lamps and Hourmeter
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Instrument Panel Lighting
Instrument Panel Lighting
IPC, MAM and BRK Fluid Level SW
Low Air Pressure Switch, MAM, IPC
ABS Indicator Lamp Relay, EBCM
EBCM, ABS Indicator Relay, IPC
Spring Assisted Park Brake, Page 1 of 2
Figure 4:

DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam and Service Engine Soon Lamps


Object Number: 778442  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Trailer, ABS, Differential Lock, Fast Idle, Intake Heater, Exhaust Brake, Do Not Shift Lamp, and Tachometer (LG5)
Illumination, Seat Belt, Primary Brake, ABS, and Park Brake Lamps
Fuse Voltage Supply
Fuse Voltage Supply
Illumination, Seat Belt, Primary Brake, ABS, and Park Brake Lamps
Trailer, ABS, Differential Lock, Fast Idle, Intake Heater, Exhaust Brake, Do Not Shift Lamp, and Tachometer (LG5)
DRL Controls
Coolant Level Switch, IPC, MAM
Charging Circuit
DRL Controls
Module Power, Ground, Serial Data, MIL
Figure 5:

Trailer ABS, Differential Lock, Fast Idle, Intake Heater, Exhaust Brake, Do Not Shift Lamps and Tachometer (LG5)


Object Number: 778433  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Fuel, Temperature, Oil Pressure and Check Gages
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Differential Lock Switch and Valve
Splice Pack 2
IPC, EBCM, ENG Exhaust Brake Switch, ECM
DRL, Service Trans Filter, Low Coolant, Oil Filter, Bat, High Beam, and Service Engine Soon Lamps
Fuel, Temperature, Oil Pressure and Check Gages
Splice Pack 2
Transmission Control Module, Power and Ground
Figure 6:

Fuel, Temperature, Oil Pressure and Check Gages (LG4)


Object Number: 778417  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Aux Brake, Apply Park Brake, RH Turn, LH Turn, Service Parke Brake Lamps and Hourmeter
Trailer, ABS, Differential Lock, Fast Idle, Intake Heater, Exhaust Brake, Do Not Shift Lamp, and Tachometer (LG5)
Fuse Voltage Supply
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361
G404, G405, G406, S402, S415, S416, S421, S422, S702
G404, G405, G406, S402, S415, S416, S421, S422, S702
Trailer, ABS, Differential Lock, Fast Idle, Intake Heater, Exhaust Brake, Do Not Shift Lamp, and Tachometer (LG5)
Figure 7:

Aux Brake, Apply Park Brake, RH Turn, LH Turn, Service Park Brake Lamps and Hourmeter


Object Number: 778439  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Exhaust Brake, Air Suspension Dump Lamps and Tachometer (LG4)
Fuel, Temperature, Oil Pressure and Check Gages
PWR BRK Booster Pump MTR and RLY
Spring Assisted Park Brake, Page 1 of 2
Front and Rear Lighting, IP Indicators
Front and Rear Lighting, IP Indicators
Spring Assisted Park Brake, Page 1 of 2
PWR BRK Booster Pump MTR and RLY
G105, S324, S326, S500
Charging Circuit
Illumination, Seat Belt, Primary Brake, ABS, and Park Brake Lamps
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361
Figure 8:

Exhaust Brake, Air Susp Dump Lamps and Tachometer (LG4)


Object Number: 778446  Size: FS
Master Electrical Component List
Instrument Cluster Description and Operation
Aux Brake, Apply Park Brake, RH Turn, LH Turn, Service Parke Brake Lamps and Hourmeter
Differential Lock Switch and Valve
Differential Lock Switch and Valve
Fuse Voltage Supply
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361
IPC, EBCM, ENG Exhaust Brake Switch, ECM
Splice Pack 2
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361
G 407, Splice Pack 3, S120, S121, S122, S150, S242, S361