GMC T-Series (T6500, T7500, T8500) (2003-2010) fuses and relays

Fuse box diagram (location and assignment of electrical fuses and relays) for GMC T-Series (T6500, T7500, T8500) (2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010).

Fuse box diagram: GMC T-Series (T6500, T7500, T8500)

Fuse box location

Instrument Panel Fuse Block

The instrument panel fuse block is located on the top of the instrument panel on the passenger’s side of the vehicle

Maxi-Fuse Block

The maxi-fuse block outside of the cab on the driver’s side of the vehicle.

Relay Blocks

There are four relay blocks in your vehicle

A – Relay Block A
B – Relay Block B
C – Relay Block C
D – Relay Block D

Fuse box diagram (Instrument Panel)

Assignment of the fuses in the Instrument Panel fuse box
NumberCircuits 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/HAZStoplamp, Turn Signals/Hazard Warning Flashers
IGN SW3Air Conditioner, Axle, Chassis
INT/EXT LIGHTSParldng 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 Stoplamps
PWR WDO/LOCKSPower Windows, Power Door Locks

Relay Block A

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

Relay Block B

Relay Block BUsage
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 CUsage
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 DUsage
1Neutral (Medium Duty Transmission)
2Back-up Lamp (Reverse) (Medium Duty Transmission)
GMC T-Series (T6500, T7500, T8500) (2003-2010) fuses and relays November 15, 2018 admin