Where are the Fuse Boxes located in the 2018 GMC Sierra?
2018 GMC Sierra has 3 main boxes with fuses and relays. One is under the hood (Engine Compartment) and two are in the Passenger Compartment i.e. on the left(Driver’s side) and another on the right(Passenger’s Side) of the Instrument Panel or Dashboard.
2018 GMC Sierra Under Dash Fuse Box and Relay Location
The auxiliary fuse box (If equipped) is located next to the interior fuse box. To open the lid, pull the tab in the direction as shown in the illustration.
There are two fuse block on either side of the Dashboard and the access door is on the driver’s side edge of the instrument panel and Passenger’s side located in the same area. Pull off the covers on either side to access the fuse block.
2018 GMC Sierra Under Hood Fuse Box and Relay location
The under hood fuse block in the engine compartment on the driver’s side of the vehicle near the battery. Lift the cover for access to the fuse relay block.
2018 GMC Sierra under Dash Fuse Box Layout
2018 GMC Sierra Under Dash Fuse Box Diagram(Left)
2018 GMC Sierra under Dash Fuse Box and Relay Details(Left)
Assignment of the fuses in the Passenger Compartment(Driver’s Side)
| No. | Usage |
| 1 | Accessory power outlet 2 |
| 2 | Special equipment option/Retained accessory power |
| 3 | Universal remote system/lnterior rearview mirror |
| 6 | Body control module 3 |
| 7 | Body control module 5 |
| 8 | Driver window switch/ Mirror switch |
| 9 | Not Used |
| 10 | Accessory power outlet/Retained accessory power |
| 11 | Accessory power outlet battery |
| 12 | Accessory power outlet 1/Cigarette lighter |
| 13 | Discrete logic ignition switch |
| 14 | Switch backlighting |
| 17 | Body control module 1 |
| 19 | Not Used |
| 20 | Not Used |
| 22 | Heating, ventilation, and air conditioning/ Auxiliary heating, ventilation, and air conditioning/lgnition |
| 23 | Instrument cluster/ Ignition sensing diagnostic module/ Ignition |
| 24 | Not Used |
| 25 | Data link connector/ Driver seat module |
| 26 | Passive entry/Passive start/Heating, ventilation, and air conditioning |
| 27 | Not Used |
| 28 | Not Used |
| 29 | Park enable/ Electrically adjustable pedals |
| 30 | Special equipment option |
| 31 | Accessory/Run/Crank |
| 32 | Heated steering wheel |
| 33 | Not Used |
| 34 | Instrument cluster |
| 36 | Not Used |
| 37 | Not Used |
| 38 | 4WD transfer case electronic control |
| 40 | Left doors |
| 41 | Driver power seat |
| 43 | Left heated, cooled or ventilated seats (if equipped) |
| 44 | Right heated, cooled or ventilated seats (if equipped) |
| 45 | Not Used |
| Relays | |
| 49 | Retained accessory power |
| 50 | Run/Crank |
2018 GMC Sierra Under Dash Fuse Box Diagram(Right)
2018 GMC Sierra under Dash Fuse Box and Relay Details(Right)
Assignment of the fuses in the Passenger Compartment(Passenger’s Side)
| No. | Usage |
| 1 | Accessory power outlet 3 |
| 2 | Accessory power outlet 4 |
| 7 | Body control module 4 |
| 8 | Body control module 8 |
| 9 | Rear seat entertainment |
| 10 | Cargo lamp |
| 15 | Steering wheel controls |
| 18 | Radio |
| 19 | Not Used |
| 20 | Sunroof |
| 23 | Airbag/lnfo |
| 26 | Export/Power take off/ Special equipment option/Battery 1 |
| 27 | Obstacle detection/ USB ports |
| 28 | Body control module 2 |
| 32 | Special equipment option/Battery 2 |
| 35 | Air conditioning inverter |
| 36 | Amplifier |
| 37 | Battery system |
| 39 | Rear sliding window |
| 42 | Right door window motor |
| 43 | Front blower |
| 44 | Special equipment option |
| 45 | Body control module 6 |
| 46 | Body control module 7 |
| 47 | Passenger seat |
| Relays | |
| 50 | Retained accessory power |
| 51 | Rear sliding window open |
| 52 | Rear sliding window close |
2018 GMC Sierra Under Hood Fuse Box Layout
2018 GMC Sierra Under Hood Fuse Box Diagram
2018 GMC Sierra under Hood Fuse Box and Relay Details
Assignment of the fuses in the Engine Compartment
| No. | Usage |
| 1 | Trailer brake |
| 2 | Trailer battery |
| 3 | Antilock brake system pump |
| 4 | Instrument panel BEC 1 |
| 5 | Passenger motorized seat belt |
| 6 | 4WD transfer case electronic control |
| 7 | Electric park brake |
| 8 | Instrument panel BEC 2 |
| 9 | Driver motorized seat belt |
| 10 | Rear window defogger |
| 11 | Starter |
| 12 | Cooling fan 1 |
| 13 | Cooling fan 2 |
| 14 | Left trailer stop/ Turn signal lamps |
| 15 | Trailer parking lamps |
| 16 | Trailer reverse lamps |
| 17 | Right trailer stop/ Turn signal lamps |
| 18 | Fuel pump |
| 19 | Integrated chassis control module |
| 20 | Electronic suspension control module |
| 21 | Fuel pump power module |
| 22 | Upfitter 1 |
| 23 | Upfitter2 |
| 24 | Front wiper |
| 25 | Antilock brake system valve |
| 26 | Upfitter 2 |
| 27 | Upfitter 3 |
| 28 | Right parking lamps |
| 29 | Left parking lamps |
| 30 | Upfitter 3 |
| 31 | Upfitter 4 |
| 32 | Upfitter 4 |
| 33 | Reverse lamps |
| 34 | Engine control module/Ignition |
| 35 | Air conditioning clutch |
| 36 | Heated mirrors |
| 37 | Upfitter 1 |
| 38 | Center high-mounted stoplamp |
| 39 | Miscellaneous/ Ignition |
| 40 | Transmission/ Ignition |
| 41 | Fuel pump 2 |
| 42 | Cooling fan clutch |
| 43 | Engine |
| 44 | Fuel injectors A–odd |
| 45 | Fuel injectors B–even |
| 46 | O2 Sensor B |
| 47 | Throttle control |
| 48 | Horn |
| 49 | Fog lamps |
| 50 | O2 Sensor A |
| 51 | Engine control module |
| 52 | Interior heater |
| 53 | Accessory power module/TPM pump |
| 54 | Front washer |
| 55 | Air conditioning/ Battery regulated voltage control |
| 56 | Air conditioning module/ Battery pack |
| 57 | Transmission control module/ Engine control module |
| 58 | Headlamps |
| 74 | Electric running boards (if equipped) |
| 76 | Fuel pump prime / MGU motor |
| 77 | Cabin pump motor |
| 79 | Vacuum pump |
| Relays | |
| 59 | Fuel pump |
| 60 | Upfitter 2 |
| 61 | Upfitter 3 |
| 62 | Upfitter 4 |
| 63 | Trailer parking lamps |
| 64 | Run/Crank |
| 65 | Upfitter 1 |
| 66 | Fuel pump 2 |
| 67 | Air conditioning control |
| 68 | Starter |
| 69 | Rear window defogger |
| 70 | Engine control module |
| 71 | Vacuum pump/ Cooling fan clutch |
| 72 | CKT 95 |
| 73 | CKT 92 |
| 75 | Fuel pump prime/ MGU motor |
| 78 | Vacuum pump switch |
WARNING: The terminal and harness assignments for individual connectors may vary depending on the vehicle’s equipment level, model, and market. It is recommended to refer to the fuse box diagram provided at the back of the fuse box cover for accurate information.
