2014 GMC Sierra 2500HD Fuse Box Diagram & Amperage

Quick Answer

The 2014 GMC Sierra 2500HD typically has three fuse box locations:

• Underhood Fuse Block: Located in the engine compartment on the driver's side, near the battery.
• Instrument Panel Fuse Block: Found on the passenger side of the instrument panel, accessible by opening the passenger door.
• Rear Under Seat Fuse Block: Situated under the rear seat on the driver's side, along with the battery.

Underhood Fuse Block

The underhood fuse block contains many of the larger fuses and relays responsible for critical engine functions, lights, and heavy-draw accessories. Always refer to the fuse legend on the underside of the fuse box cover for the most accurate information for your specific trim level.

Relay Locations (Common):

• RUN/CRNK Relay: Controls power to various circuits during ignition run and crank.
• Fuel Pump Relay: Powers the fuel pump.
• Starter Relay: Engages the starter motor.
• Blower Motor Relay: Powers the HVAC blower motor.
• A/C Clutch Relay: Engages the A/C compressor clutch.
• Headlamp Relays: Control the high and low beam headlights.

Instrument Panel Fuse Block

This fuse block primarily handles interior electrical components and accessories. It's located on the passenger side of the instrument panel, against the kick panel. Open the passenger door to access it.

Rear Under Seat Fuse Block

This fuse block is located under the rear seat on the driver's side, often alongside the vehicle's primary battery. It typically handles power for systems located towards the rear of the vehicle, as well as some heavy-duty accessories.

How to Test a Fuse

Testing a fuse is a straightforward process that can save you time and money. Here's how:

1. Locate the Fuse Box: Identify the correct fuse box for the circuit you're troubleshooting.
2. Remove the Fuse: Use the fuse puller (usually found in the underhood fuse block) to carefully remove the suspect fuse. Hold the fuse by the body, not the blades, to avoid damaging it.
3. Visual Inspection: Hold the fuse up to a light and look at the small wire or filament inside. If the wire is broken or melted, the fuse is blown and needs to be replaced.
4. Multimeter Test (Recommended): For a more accurate test, use a multimeter set to the continuity or ohmic resistance setting. Touch the probes to the metal contact points on the top of the fuse. If the multimeter shows continuity or a very low resistance (close to zero ohms), the fuse is good. If it shows "OL" (open loop) or infinite resistance, the fuse is blown.
5. Replace with Correct Amperage: ALWAYS replace a blown fuse with a new fuse 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 to failure due to their circuits' demands or common issues. On the 2014 GMC Sierra 2500HD, these are often reported:

• Cigar Lighter / 12V Power Outlets (Instrument Panel & Rear): These fuses (typically 20A Yellow in the instrument panel and rear fuse blocks) frequently blow due to over-drawing current from charging multiple devices or using high-power accessories. Check the devices plugged in first. Unplug everything and replace the fuse. If it blows again, there might be a wiring issue.
• Trailer Brake Control (TBC): The 30A Green fuse (underhood) for the trailer brake control can blow if there's a short in the trailer wiring or if the trailer brakes are overloaded. Inspect your trailer's wiring harness for damage or corrosion first, especially the connector.
• Blower Motor: The 30A Green fuse (underhood) protecting the blower motor can fail, particularly if the blower motor is old or struggling, drawing excessive current. If the fuse blows immediately, the motor might be seized or the resistor bad. Check for any obstructions in the blower motor fan first.
• Headlights: While less common, headlight fuses (10A Red and 20A Yellow underhood) can blow, often indicating a problem with a specific bulb or wiring. Check the headlight bulbs first for signs of being burnt out.
• Radio / Infotainment: The 15A Blue fuse (instrument panel) for the radio can blow, often related to aftermarket stereo installations or a short within the unit itself. Ensure no aftermarket accessories are shorting the circuit.

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