2020 GMC Sierra 2500HD Fuse Box Diagram & Amperage
Your comprehensive guide to fuse box locations, diagrams, and common issues for your heavy-duty truck.
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Quick Answer
The 2020 GMC Sierra 2500HD features three main fuse box locations: the under-hood fuse box, the instrument panel (dash) fuse box, and the rear under-seat fuse box.
Under-Hood Fuse Box
The under-hood fuse box is located in the engine compartment on the driver's side, near the battery. This box contains fuses and relays for critical engine functions, main power distribution, and several high-current accessories. Always consult the diagram on the fuse box lid for the most accurate information for your specific trim level.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 15A | Blue | ECM/PCM (Engine Control Module/Powertrain Control Module) |
| F2 | 20A | Yellow | Fuel Pump Relay |
| F3 | 30A | Green | Ignition Switch |
| F4 | 25A | Clear | Starter Solenoid / Relay |
| F5 | 10A | Red | Low Beam Headlight (Driver Side) |
| F6 | 10A | Red | Low Beam Headlight (Passenger Side) |
| F7 | 15A | Blue | High Beam Headlight (Driver Side) |
| F8 | 15A | Blue | High Beam Headlight (Passenger Side) |
| F9 | 10A | Red | Tail Lights |
| F10 | 10A | Red | Park Lights |
| F11 | 40A | Green | Blower Motor (HVAC) |
| F12 | 10A Red | A/C Clutch Relay | |
| F13 | 30A | Green | ABS (Anti-lock Brake System) Pump |
| F14 | 10A | Red | ABS Module |
| F15 | 20A | Yellow | Trailer Brake Control Module |
| F16 | 10A | Red | Main Power Relay (Various circuits) |
| F17 | 15A | Blue | Trailer Stop/Turn (Left) |
| F18 | 15A | Blue | Trailer Stop/Turn (Right) |
| F19 | 20A | Yellow | Trailer Backup Lamps |
| F20 | 30A | Green | Trailer Power (Battery Charge) |
Relay Locations (Under-Hood):
The under-hood fuse box also houses several important relays:
- Fuel Pump Relay: Typically located near the fuel pump fuse (F2).
- Starter Relay: Often paired with the starter solenoid fuse (F4).
- Main Power Relay: Controls power to various circuits.
- Blower Motor Relay: Controls the high-current blower motor.
- A/C Clutch Relay: Activates the air conditioning compressor clutch.
- Trailer Brake Relay: Power for the trailer brake control system.
Instrument Panel Fuse Box
The instrument panel fuse box is located on the passenger side, behind the kick panel. To access it, you will need to remove the kick panel trim. This fuse box primarily handles interior electrical components, infotainment, various cabin accessories, and some body control module functions. Refer to the diagram on the fuse box cover for your exact vehicle configuration.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 10A | Red | Radio / Infotainment System |
| F2 | 15A | Blue | Cigar Lighter / 12V Power Outlet (Front) |
| F3 | 15A | Blue | HVAC Controls / Climate Control |
| F4 | 10A | Red | Airbag (SIR) Module |
| F5 | 20A | Yellow | Power Windows (Driver) |
| F6 | 20A | Yellow | Power Windows (Passenger) |
| F7 | 10A | Red | Interior Lights (Dome, Map) |
| F8 | 10A | Red | Instrument Cluster |
| F9 | 10A | Red | Body Control Module (BCM) |
| F10 | 15A | Blue | OnStar / Telematics |
| F11 | 10A | Red | USB Ports |
| F12 | 15A | Blue | Sunroof (If Equipped) |
| F13 | 20A | Yellow | Heated Seats (If Equipped) |
| F14 | 10A | Red | Wiper Motor Control |
| F15 | 15A | Blue | Accessory Power Outlet (Console) |
Rear Under-Seat Fuse Box
The 2020 GMC Sierra 2500HD may have a third fuse box located under the rear seats, often on the driver's side. This fuse box typically handles power for rear passenger accessories, additional trailering functions, and some heavy-duty options. Lift the rear seat bottom to access it. Always check your specific owner's manual and the fuse box lid for exact configurations.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 20A | Yellow | 12V Power Outlet (Rear) |
| F2 | 30A | Green | Trailer Backup Lamp Power |
| F3 | 15A | Blue | Power Inverter (120V Outlet, If Equipped) |
| F4 | 10A | Red | Rear Axle Lock Module (If Equipped) |
| F5 | 20A | Yellow | Cargo Area Lighting |
| F6 | 25A | Clear | Power Running Boards (If Equipped) |
| F7 | 15A | Blue | Trailer Camera Power |
| F8 | 30A | Green | Snow Plow Prep Package (If Equipped) |
How to Test a Fuse
Testing a fuse is a straightforward process:
- Safety First: Always turn off the ignition and remove the key before working with fuses.
- Locate the Blown Fuse: Visually inspect the fuse. A good fuse will have a continuous wire or metal strip inside. A blown fuse will have a broken or melted strip. Newer fuses may have a small LED that illuminates when blown.
- Use a Fuse Tester: For a more reliable test, use a fuse tester or a multimeter. With the fuse removed from its slot, touch the tester probes to the two metal terminals on the fuse. A good fuse will show continuity or light up the tester. If there's no continuity or light, the fuse is blown.
- Replace with Correct Amperage: Always replace a blown fuse with a new one of the exact same amperage rating and type. Using a fuse with a higher amperage can lead to serious electrical damage or fire.
Common Blown Fuses on This Vehicle
While any fuse can blow, some are more prone due to the nature of their circuits. On the 2020 GMC Sierra 2500HD, common culprits can include:
- Cigar Lighter / 12V Power Outlet Fuses (Instrument Panel F2, Rear Under-Seat F1): These frequently blow due to overcurrent from charging multiple devices or using high-power accessories. Always check the connected accessories first.
- Trailer Brake Control Module Fuse (Under-Hood F15): Issues with trailer wiring or a short in the trailer's electrical system can cause this fuse to blow. Inspect your trailer wiring if you experience brake controller issues.
- Blower Motor Fuse (Under-Hood F11): A failing blower motor or a blockage in the HVAC system forcing the motor to work harder can lead to this fuse blowing. Check for obstructions in the blower motor housing.
- Headlight Fuses (Under-Hood F5-F8): While less common, a short in the headlight wiring or a faulty bulb can cause these to blow. Check your bulbs and wiring.
- Radio / Infotainment Fuse (Instrument Panel F1): Issues with aftermarket accessories or even an internal short in the head unit can cause this fuse to blow. If issues persist after replacement, consider having the infotainment system inspected.
Always remember to consult your owner's manual for the most accurate and detailed fuse box diagrams and information specific to your vehicle's trim level and options.
Find a trusted shop on Repairius.
Before you pull a fuse on the 2020 GMC Sierra 2500HD
- Use the label printed on the panel cover or the owner's manual for your exact build. Layouts change with options, model year and build date, so a chart for another truck can be wrong.
- Replace a blown fuse only with the same amp rating. A larger fuse can let wiring overheat.
- A fuse that blows again right away means a short or failing component downstream. Find the cause before replacing it again.
- A good fuse doesn't prove the circuit works — relays, grounds and connectors fail too.
- Disconnect the battery before working near high-current fuses or cables.
Learn more: How fuses, relays and truck electrical systems work
More specs for the 2020 GMC Sierra 2500HD
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
2014 Sierra 2500HD
2015 Sierra 2500HD
2016 Sierra 2500HD
2017 Sierra 2500HD
2018 Sierra 2500HD
2019 Sierra 2500HD
Maintenance & repair guides
2020 GMC Sierra 2500HD Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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