GMC Sierra 1500 Fuse Box: Location & Guide
TL;DR
Sierra 1500 fuses live in an underhood block by the battery and an interior block under the driver-side dash; use the lid diagram or owner's manual for exact fuse assignments, not a generic chart.
Where the fuse boxes are located
Across every generation of the Sierra 1500, GMC uses the same basic layout: a larger underhood fuse and relay block mounted in the engine bay, typically near the battery on the driver side, and a smaller interior fuse block mounted under the dashboard on the driver's side. The underhood box has a hinged or snap-on plastic lid held by tabs or clips - press the release tabs and lift straight up to open it. The interior block is usually hidden behind a plastic kick panel or a small access cover to the left of the steering column or near the driver's door; it typically pulls straight off or unclips by hand, no tools required.
Fuse box by generation
| Generation / years | Fuse box | Typical location | How to access |
|---|---|---|---|
| GMT800 (1999-2006) | Underhood block | Engine bay, driver side near battery | Unclip plastic lid tabs, lift off |
| GMT800 (1999-2006) | Interior block | Under dash, driver side, left of steering column | Remove small cover panel by hand |
| GMT900 (2007-2013) | Underhood block | Engine bay, driver side near battery | Press release tabs, lift lid |
| GMT900 (2007-2013) | Interior block | Under dash, driver side kick panel area | Pull kick panel or cover off |
| K2XX (2014-2018) | Underhood block | Engine bay, driver side near battery | Unclip lid, lift straight up |
| K2XX (2014-2018) | Interior block | Under dash, driver side near door | Unclip trim cover by hand |
| T1 (2019-present) | Underhood block | Engine bay, driver side near battery | Unclip and lift lid |
| T1 (2019-present) | Interior block | Under dash, driver side lower panel | Unclip lower dash panel by hand |
Where the official fuse legend lives
Every fuse box lid or cover has a printed diagram molded or stickered onto the inside showing each fuse's circuit and amperage. This diagram is the authoritative source for your specific vehicle - it accounts for trim-level and option differences (trailer brake controller, plow prep package, etc.) that a generic chart cannot. The same information is duplicated in the owner's manual, in the electrical section that covers fuses and circuit breakers, which also explains any color-coding used on the fuse pull tool.
Fuses that commonly cause complaints
By function rather than position, the circuits owners most often report trouble with are: the cigarette lighter / 12V accessory outlet fuse, which blows from phone chargers, inverters, or aftermarket accessories left plugged in; the radio / infotainment fuse, which can cause the screen or stereo to go dark; the interior lighting fuse, covering dome, dash, and courtesy lights; the blower motor fuse or relay, which causes total loss of heat or A/C airflow when it fails; and the fuel pump relay circuit, which can cause a no-start or stalling condition. Any of these can also fail at the relay itself rather than the fuse, so both should be checked.
Checking and replacing a fuse
Pull the suspect fuse using the plastic puller tool usually clipped inside the fuse box lid, and hold it up to the light - a blown fuse shows a visibly broken or melted metal strip inside the clear plastic body. For a more reliable check, use a test light or multimeter across the two prongs with the circuit powered on; no reading on one side with the fuse in place confirms it is open. Always replace a blown fuse with one of the same amperage rating printed on the lid diagram - never a higher rating, which removes the protection the circuit is designed around and risks wiring damage or fire.
When a fuse keeps blowing
A fuse that blows again shortly after replacement, especially more than once, points to a short circuit or a failing component drawing excess current rather than a bad fuse itself. In that case, stop replacing fuses and have the vehicle scanned for stored diagnostic trouble codes, which can point technicians toward the specific circuit or module at fault before further diagnosis or repair.
Because exact fuse numbering and amperage vary by model year, engine, and options, always confirm details for your specific truck using the diagram on your fuse box lid or the owner's manual for your build year.
Summary
| Underhood fuse block location | Engine bay, driver side, near the battery |
|---|---|
| Interior fuse block location | Under dash, driver side, behind kick panel/cover |
| Fuse legend source | Diagram on inside of fuse box lid + owner's manual |
| Common trouble fuses | 12V outlet, radio/infotainment, interior lights, blower motor, fuel pump relay |
| How to check a fuse | Visual inspection of element, or test light/multimeter across prongs |
| Replacement rule | Match printed amperage rating exactly, never go higher |
| Repeated blowing means | Likely short circuit - scan for stored fault codes |
Full diagnostics
For the complete step-by-step diagnostic and repair guide, see GMC Sierra 1500: Common Problems, Fault Codes & Repairs.
Frequently asked questions
Where is the main fuse box on a GMC Sierra 1500?
The GMC Sierra 1500 has two fuse boxes on every generation: a larger underhood fuse and relay block in the engine bay near the battery on the driver side, and a smaller interior fuse block under the dashboard on the driver's side, usually behind a small kick panel or cover. Which one controls a given circuit is shown on the diagram printed inside each box's lid.
Why does my Sierra 1500's cigarette lighter or 12V outlet keep blowing a fuse?
The 12V accessory outlet fuse on the Sierra 1500 commonly blows from phone chargers, power inverters, or aftermarket accessories drawing too much current, or from a short in the accessory plug itself. Replace it with a fuse of the same amperage shown on the fuse box lid diagram, and if it blows again quickly, the outlet or an attached accessory likely has a short that needs diagnosing rather than repeated fuse swaps.
How do I know which fuse controls the radio or blower motor on my Sierra 1500?
GMC does not use one fixed fuse number across all Sierra 1500 model years, so the correct way to find the radio, blower motor, or any other circuit's fuse is to read the diagram printed on the inside of the interior or underhood fuse box lid for your specific truck, or the fuses and circuit breakers section of its owner's manual.
What does it mean if a fuse on my Sierra 1500 keeps blowing after I replace it?
A fuse that blows again soon after being replaced almost always indicates a short circuit or a component drawing too much current, not a defective fuse. Continuing to replace the fuse risks wiring damage, so the truck should be scanned for stored diagnostic trouble codes and the affected circuit inspected before installing another fuse.