Year of production: 2008, 2009
                        
                        
                    Instrument Panel Fuse Block
There are two instrument panel fuse blocks located behind the instrument panel on the passenger’s side of the vehicle.
| Circuit Breaker | Usage | 
| 1 | Stoplamps | 
| 2 | Not Used | 
| 3 | Parking Lamps | 
| 4 | Powertrain Control Module | 
| 5 | Auxiliary Wiring | 
| 6 | Heater/Air Conditioning | 
| 7 | Hazard Warning Flashers | 
| 8 | Power Post | 
| 9 | Courtesy Lamps | 
| 10 | Warning Lights, Gages and Indicators | 
| 11 | Starter | 
| 12 | Rear Axle/Four-Wheel-Drive | 
| 13 | Trailer Turn Signals/Hazard Warning Flashers | 
| 14 | Radio/Chime | 
| 15 | Daytime Running Lamps | 
| 16 | Airbag System | 
| 17 | Exterior/Interior Lamps | 
| 18 | Parking Brake | 
| 19 | Accessory Power | 
| 20 | Ignition 4 | 
| 21 | Sidemarker Lamps | 
| 22 | Turn Signal/Backup Lamps | 
| 23 | Transmission | 
| 24 | Hydraulics/Air Brake | 
| A | Spare | 
| B | Spare | 
| Fuse | Usage | 
| Blanj | Not Used | 
| RT PRK | Passenger’s Side Parking Lamps | 
| Blank | Not Used | 
| Blank | Not Used | 
| LT PARK | Driver’s Side Parking Lamps | 
| RT REAR TRN/STOP | Passenger’s Side Rear Turn Signal/Stoplamp | 
| LT REAR TRN/STOP | Driver’s Side Rear Turn Signal/Stoplamp | 
| RADIO | Radio | 
| Blank | Not Used | 
| Blank | Not Used | 
| PWR WNDW | Power Windows | 
| Relay | Usage | 
| ECU/PTO* | Engine Control Unit/Power Take-Off *Diesel 7.8 DURAMAX® | 
| BRK LAMP | C4/C5 Brake Lamps, C6/C7/C8 Tractor/Trailer Wiring | 
| DRL | Daytime Running Lamps | 
| IGN-4 | Ignition | 
| CHMSL | Center High Mounted Stop Lamp | 
| MRK LTS | Sidemarker and Clearance Lamps | 
| HTD/MIRR | Heated Mirrors | 
| HTR | Diesel Heated Fuel | 
| RT TRN TRLR | Passenger’s Side Trailer Turn Signal | 
| Blank | Not Used | 
| LT TRN TRLR | Driver’s Side Trailer Turn Signal | 
| Blank | Not Used | 
| Blank | Not Used | 
| Blank | Not Used | 
Underhood Fuse Block
Fuse blocks are located in the engine compartment, on the passenger’s side of the vehicle.
Primary Underhood Fuse Block
| Fuse | Usage | 
| RR DEFOG | Rear Defog | 
| ENG 1 | Engine 1 | 
| ENG 3 | Engine 3 (L18/LF6/LF8) | 
| PCM-B | Powertrain Control Module | 
| TCM | Transmissions (LF8) | 
| ENG 4 | Engine 4 (LMM/LF6/LF8) | 
| ENG 2 | Engine 2 (L18/LMM) | 
| HTD FUEL | Heated Fuel (LMM) | 
| BLANK | Not Used | 
| BLANK | Not Used | 
| NOTE 3 | Fan Relay (LMM), Emissions (L18) | 
| A/C COMP | Air Conditioning Compressor | 
| ABS 1 | Anti-lock Brake System 1 | 
| ABS 2 | Anti-lock Brake System 2 | 
| ABS 3 | Anti-lock Brake System 3 | 
| ENGINE | Engine | 
| E/A PUMP | Electronic/Automatic Pump | 
| HORN | Horn | 
| NOTE 2 | Fuel (L18/LMM), Electronic Control Module (LF6) | 
| NOTE 3 | Electronic Control Module (LF6) | 
| STUD A | Spare | 
| STUD B | Spare | 
| Relay | Usage | 
| NOTE 1 | LMM/L18 Fuel Pump Relay | 
| IGN B RELAY | Ignition Relay | 
| STARTER RELAY | Starter Relay | 
| HORN RELAY | Horn Relay | 
| IGN A RELAY | Ignition Relay | 
| PTO/ECU* RELAY | Power Take-Off/Engine Control Unit (*Diesel 7.8L LF8) | 
| REVERSE RELAY | Reverse Relay | 
| FAN RELAY | Fan Relay (LMM) | 
Secondary Underhood Fuse Block
| Fuse | Usage | 
| IGN 1 | Ignition 1 | 
| IGN 4 | Ignition 4 | 
| IGN 3 | Ignition 3 | 
| BATT/HAZ | Battery/Hazard Warning Flashers | 
| HEADLAMP | Headlamps | 
| LIGHTING | Interior/Exterior Lamps | 
| HVAC | Climate Control System | 
| NOTE | C4/C5 Electric Brake, C6/C7/C8 Brake Lamps | 
WARNING: Terminal and harness assignments for individual connectors will vary depending on vehicle equipment level, model, and market.



