2003-2010 GMC T-Series (T6500, T7500, T8500) fuse box diagram

This article provides fuse box diagrams for GMC T-Series trucks (T6500, T7500, T8500) from 2003 to 2010. It shows where the fuse panels are located inside the vehicle and explains which fuse controls each component and relay.

Cigar lighter (power outlet) fuse in the GMC T6500, T7500, T8500 is the fuse #2 in the Instrument panel fuse box.

Instrument Panel

Circuits Protected
1Ignition Switch
2Cigarette Lighter
3ECM Ignition 1
4Truck Body Controller
5ALDL Connector
6Warning Lamp, Ignition Relay, Blower Motor, Motor Relay, Auxiliary Relay, Power Window Relay, INT Relay
7Room Lamp, Horn, Electric Parking Brake, Radio Back Up, Rear Body Dome Lamp
8Power Window
9Exhaust Brake Back Up, Air Suspension Dump, Differential Lock, Air Dryer, Moisture Ejection Heater, Electric Air Compressor, Power Take Off
10ECM Ignition Power
11Trailer Turn (LH) Lamp
12Auxiliary (Ignition ON)
13Auxiliary (Battery Direct)
14Headlamp (LH)
15Headlamp (RH)
17Heated Fuel
18Meter Truck Body Controller
19ID Lamp, Marker Lamp, Tail Lamp, Lighted Mirror, Illumination Lamp
20Cool Condenser Fan Motor, Cooler Compressor
21Wiper Motor, Washer Motor
22Heated Mirror, Two-Speed Axle Relay
24Blower Motor, Air Conditioner Relay
25Trailer Turn (RH) Lamp, Flasher Unit
26Power Post (Consent)

Assignment of the fuses in the Maxi-Fuse Block

NameCircuits/Circuit Breakers Protected
ST/TURN/HAZStop lamp, Turn Signals/Hazard Warning Flashers
IGN SW3Air Conditioner, Axle, Chassis
INT/EXT LIGHTSPurling Lamps, Dome Lamp, Instrument Panel Lights
HEAD LAMPHeadlamps, Daytime Running Lamps
AUX WRGAuxiliary, Parking Brake
IGN SW1Ignition Switch, Washer/Wiper, Crank, Radio
HYD PUMPHydraulic Brake, Brake Pump Motor
ABSAnti-Lock Brake System Module
ELECT TRANSIgnition Relay
PARK BRAKEParking Brake Motor
BLOWER HORNBlower, Horn, Cigarette Lighter, Auxiliary
TRAILER ABSTrailer Anti-Lock Brake System, Trailer Stop lamps
PWR WDO/LOCKSPower Windows, Power Door Locks

Relay Block A

Relay Block ADescription
1Power Window
2Back Lamp (Reverse)
3High Beam
5Lighting (Low, High)
6Trailer Turn Signal (Left Headlamp)
7Tail Lamp
8Marker Lamp
9Trailer Turn Signal (Right Headlamp)

Relay Block B

Relay Block BDescription
1Air Conditioning Condenser (If Equipped)
2Air Conditioning Compressor (If Equipped)
3Heater Fan
4Ignition (Accessory)
5Ignition 1
6Ignition 2
9Ignition 3
10Dome Lamp (If Equipped)
11Exhaust Brake (If Equipped)
12Power Take Off Control (If Equipped)

Relay Block C

Relay Block CDescription
1Parking Brake
2Daytime Running Lamps (DRL) On (Engine Run)
3Daytime Running Lamps (DRL) Off (Parking)
4Parking Lamps/Daytime Running Lamps (DRL)
5Fuel Filter (Heated Fuel)
6Stop Lamp

Relay Block D

Relay Block DDescription
1Neutral (Medium Duty Transmission)
2Back-up Lamp (Reverse) (Medium Duty Transmission)
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Tom Smith is a passionate car mechanic and automotive enthusiast, specializing in the intricate world of car fuse boxes. With years of hands-on experience under the hood, he has earned a reputation as a reliable expert in his field. As the founder and content creator of the popular blog website 'carsfuse.com,' Tom has dedicated himself to sharing his extensive knowledge of car fuse boxes and electrical systems with the world.

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