The wiring circuits in your vehicle are protected from short circuits by a combination of fuses, circuit breakers, maxi-fuses and fusible links. This greatly reduces the chance of a fire caused by an electrical problem. There may be a fuse taped to the wiring harness near the hydraulic brake booster.
Instrument Panel Fuse Block and Maxi-Fuse Block
There are two fuse blocks in your vehicle: the instrument panel fuse block and the maxi-fuse block.
The fuse block is located on the top of the instrument panel on the passenger's side of the vehicle.
To access the fuse block, remove the cover by lifting up on the front and turning it backward.
To reinstall the cover, put the tabs at the rear of the cover into the slots on the instrument panel and lower the cover down to snap into place.
If you ever have a problem on the road and don't have a spare fuse, you can borrow one of the correct value. Just pick some feature of your vehicle that you can get along without, like the radio or cigarette lighter, and use its fuse if it is the value you need. Remember to replace the fuse as soon as you can.
These fuses are non-cycling; do not replace them with cycling fuses. Also, do not use fuses of a higher amperage than those listed on the circuit breaker block.
Fuses | Usage |
|---|---|
1 | Ignition Switch |
2 | Cigarette Lighter |
3 | ECM Ignition 1 |
4 | Truck Body Controller |
5 | ALDL Connector |
6 | Warning Lamp, Ignition Relay, Blower Motor, Motor Relay, Auxiliary Relay, Power Window Relay, INT Relay |
7 | Room Lamp, Horn, Electric Parking Brake, Radio Back Up, Rear Body Dome Lamp |
8 | Power Window |
9 | Exhaust Brake Back Up, Air Suspension Dump, Differential Lock, Air Dryer, Moisture Ejection Heater, Electric Air Compressor, Power Take Off |
10 | ECM Ignition Power |
11 | Trailer Turn (LH) Lamp |
12 | Auxiliary (Ignition ON) |
13 | Auxiliary (Battery Direct) |
14 | Headlamp (LH) |
15 | Headlamp (RH) |
16 | Headlamp |
17 | Heated Fuel |
18 | Meter Truck Body Controller |
19 | ID Lamp, Marker Lamp, Tail Lamp, Lighted Mirror, Illumination Lamp |
20 | Cool Condenser Fan Motor, Cooler Compressor |
21 | Wiper Motor, Washer Motor |
22 | Heated Mirror, Two-Speed Axle Relay |
23 | Empty |
24 | Blower Motor, Air Conditioner Relay |
25 | Trailer Turn (RH) Lamp, Flasher Unit |
26 | Power Post (Consent) |
Maxi-Fuse Block
When a fuse goes out, first check the instrument panel fuse block. If there are no fuses out, the problem could be in the maxi-fuse block.
The maxi-fuse block outside of the cab on the driver's side of the vehicle. To access the maxi-fuse block, remove the four screws from the front of the box and remove the cover.
Power is fed through these fuses to devices such as the headlamp switch, ignition switch feed circuits and the auxiliary brake pump (hydraulic brake vehicles).
Do not use maxi-fuses of higher amperage than those indicated on the maxi-fuse block.
Fuses | Usage |
|---|---|
ST/TURN/HAZ | Stoplamp, Turn Signals/Hazard Warning Flashers |
IGN SW 3 | Air Conditioner, Axle, Chassis |
INT/EXT LIGHTS | Parking Lamps, dome Lamp, Instrument Panel Lights |
HEAD LAMP | Headlamps, Daytime Running Lamps |
AUX WRG | Auxiliary, Parking Brake |
IGN SW 1 | Ignition Switch, Washer/Wiper, Crank, Radio |
HYD PUMP | Hydraulic Brake, Brake Pump Motor |
ABS | Anti-Lock Brake System Module |
ELECT TRANS | Ignition Relay |
PARK BRAKE | Parking Brake Motor |
BLOWER HORN | Blower, Horn, Cigarette Lighter, Auxiliary |
TRAILER ABS | Trailer Anti-Lock Brake System, Trailer Stoplamps |
PWR WDO/LOCKS | Power Window, Power Door Locks |
Relay Blocks
There are three relay blocks in your vehicle:
Relay Block A
Relay Block B
Relay Block C
Relay Block A
Relay Block A | Usage |
|---|---|
1 | Power Window |
2 | Back Lamp (Reverse) |
3 | High Beam |
4 | Lighting |
5 | Lighting (Low, High) |
6 | Trailer Turn Signal (Left Headlamp) |
7 | Tail Lamp |
8 | Marker Lamp |
9 | Trailer Turn Signal (Right Headlamp) |
Relay Block B
Relay Block B | Usage |
|---|---|
1 | Air Conditioning Condenser |
2 | Air Conditioning Compressor |
3 | Heater Fan |
4 | Ignition Accessory |
5 | Ignition 1 |
6 | Ignition 2 |
7 | Auxiliary |
8 | Horn |
9 | Ignition 3 |
10 | Dome Lamp |
11 | Exhaust Brake |
12 | Power Take Off Control |
Relay Block C
Relay Block C | Usage |
|---|---|
1 | Parking Brake |
2 | Daytime Running Lamps On |
3 | Daytime Running Lamp Off |
4 | Parking Lamps/Daytime Running Lamps |
5 | Neutral |
6 | Stop Lamp |
