2020 Chevrolet Silverado 3500HD Fuse Box Diagram & Amperages

As an ASE-certified master technician, I know how frustrating electrical gremlins can be, especially on heavy-duty workhorses like the 2020 Chevrolet Silverado 3500HD. Whether your trailer brakes suddenly lost power, your 12V accessory outlet went dead, or your infotainment screen went black, checking the fuses is always the first diagnostic step.

This guide covers the fuse box locations, amperage ratings, color codes, and protected circuits for the 2020 Chevy Silverado 3500HD. Keep in mind that exact fuse placements can vary slightly depending on your engine (6.6L Gas vs. 6.6L Duramax Diesel) and trim level (WT, LT, LTZ, High Country). Always verify the printed legend on the inside of your fuse box lid before pulling or replacing a fuse.

Quick Answer: Fuse Box Locations

On the 2020 Chevrolet Silverado 3500HD, you will find three main fuse blocks:

1. Under-hood Fuse Block: Located in the engine compartment on the passenger side, near the battery.
2. Left Instrument Panel Fuse Block: Located inside the cabin on the driver's side, behind a removable panel on the side of the dashboard.
3. Right Instrument Panel Fuse Block: Located inside the cabin on the passenger's side, behind a removable panel on the side of the dashboard.

Under-hood Fuse Block

The under-hood fuse block handles high-amperage circuits, engine management (ECM/PCM), exterior lighting, anti-lock brakes (ABS), and major relays like the starter and A/C clutch.

Note: Diesel models (Duramax) will have additional fuses for the glow plug module, DEF heater, and fuel water sensor.

Left Instrument Panel Fuse Block

The left instrument panel fuse block (driver's side) primarily controls interior electronics, body control module (BCM) functions, door locks, and driver-side accessories.

Right Instrument Panel Fuse Block

The right instrument panel fuse block (passenger's side) handles climate control systems, passenger-side accessories, and some auxiliary trailer power feeds.

How to test a fuse

It is common to suspect a blown fuse when a specific electrical component stops working. Before throwing parts at the truck, test the fuse properly.

1. Visual Inspection: Pull the suspect fuse using the plastic puller tool stored in the under-hood fuse block. Look at the U-shaped wire inside the colored plastic. If the wire is broken or scorched, the fuse is blown.
2. Use a Test Light: This is a faster method, especially for testing multiple fuses. Turn the ignition to the "ON" position. Attach the ground clip of your 12V test light to a good, bare metal ground. Touch the probe to the small metal test points on the top of each fuse. The light should illuminate on both sides of the fuse. If it only lights up on one side, the fuse is blown.
3. Use a Multimeter: Set your digital multimeter to the continuity setting (the one that beeps). Touch a probe to each metal test point on top of the fuse. A continuous beep means the fuse is good. No beep means it's blown.

Pro-tip: Never replace a blown fuse with one of a higher amperage rating. Doing so bypasses the safety limit of the circuit and can melt wiring or start an electrical fire.

Common blown fuses on this vehicle

Working on heavy-duty Silverados regularly, I see the same fuses blow time and time again. If you're having issues, check these first:

• Trailer Fuses (F31, F64 under-hood): HD trucks tow heavy, often using trailers with questionable wiring. A short in your trailer's lighting or braking system will instantly pop the truck's trailer fuses. If your trailer lights or brakes aren't working, check the under-hood fuses and test the trailer plug receptacle at the bumper.
• 12V Outlets / Cigar Lighter (F01 Left Dash): Phone chargers, tire inflators, and power inverters frequently draw too much current or have internal shorts, popping the 20-amp interior fuses.
• Fuel Pump Fuse (F14 under-hood): If the truck cranks but won't start, listen for the fuel pump priming when you turn the key on. If it's silent, check the fuel pump fuse and relay. Keep in mind that a blown fuel pump fuse can sometimes indicate a failing, high-resistance fuel pump.

Electrical diagnosis can be tricky. If you keep blowing the same fuse, you have a short to ground in the wiring or a failed component that is drawing too much amperage. Don't risk electrical damage to your truck. Find a trusted shop on Repairius.