GMC Sierra Fuel Pump Relay Location: Complete Guide for All Model Years

If your GMC Sierra cranks but won’t start, the fuel pump relay is one of the first things to check. The fuel pump relay on most GMC Sierra trucks is located in the under-hood fuse box (Power Distribution Center) on the driver’s side of the engine compartment. However, the exact location can vary depending on the model year. This guide covers every generation from 1988 to 2020, so you can find and test the relay quickly.

Where Is the Fuel Pump Relay on a GMC Sierra?

The fuel pump relay controls power to the fuel pump. When you turn the key to the “ON” position, the relay should click and send voltage to the pump. If the relay fails, the pump won’t run, and the engine won’t start.

For most GMC Sierra trucks, the relay is inside the under-hood fuse/relay box, often called the Power Distribution Center (PDC). This box is typically located on the driver’s side near the firewall or strut tower. The relay is usually labeled “FUEL PUMP” or “F/PMP” on the diagram inside the lid .

Here is the breakdown by generation:

1988-1998 GMC Sierra (GMT400 Platform)

On these older trucks, the fuel pump relay is located in the engine compartment fuse block. The exact placement varies by year:

  • 1991-1993 models: The relay is mounted on the driver’s side firewall/fender skirt, above and forward of the brake booster. Look for a small plastic cover with writing such as “Power block” or “Fuel pump relay” . Some sources note it sits directly below the passenger-side windshield wiper on the firewall .
  • 1994-1996 models: The fuel pump relay is typically in the underhood fuse block on the driver’s side. For a 1996 Sierra, it is found in position R21 .
  • 1997-1998 models: The relay remains in the underhood fuse block. On the 1997 Sierra, the fuse box diagram specifically lists a “FUEL PUMP RELAY” in the main under-hood block .

1999-2006 GMC Sierra (GMT800 Platform)

These trucks use a larger under-hood fuse box. The fuel pump relay is inside the main engine compartment fuse block, located on the driver’s side near the battery. Open the cover and look for the “F/PMP” label on the diagram . This generation covers the 4.8L, 5.3L, and 6.0L V8 engines.

2007-2013 GMC Sierra (GMT900 Platform)

For 2007-2013 models, the fuel pump relay is in the Power Distribution Center (PDC) under the hood. It is labeled “FUEL PUMP” on the diagram inside the lid. The PDC sits on the driver’s side of the engine bay. This applies to both the 1500 and 2500/3500 HD models .

2014-2020 GMC Sierra (K2XX Platform)

On newer models, the fuel pump relay is still in the engine compartment fuse block, but the layout has changed. The fuse box is on the driver’s side of the engine compartment. For 2014-2020 trucks, look for a micro relay labeled “FUEL PUMP” (often position 60) and a separate fuse for the fuel pump (position 18) . Some models also have a “Fuel Pump Power Module” as a separate component .

2020 and Newer Models

On the latest generation (2020+), the fuel pump relay is included in the under-hood fuse block. The diagram shows relay “R5” as the fuel pump relay on 2007+ models, and newer models continue this pattern .

How to Test the Fuel Pump Relay

Before replacing parts, test the relay. Here is a simple method:

1. Swap the relay with a known-good one. Find a relay of the same type in the same fuse box (like the horn relay or A/C relay). Swap them. If the truck starts or the fuel pump hums, the original relay was bad .

2. Listen for the pump. Turn the ignition to “ON” (but don’t crank). You should hear a 2-3 second whirring sound from the fuel tank. No sound means the relay or pump isn’t getting power.

3. Check for voltage. Use a multimeter to test the relay’s input and output terminals with the key in the “ON” position. You should see 12 volts at the input. If voltage is present but the relay doesn’t click, the relay is faulty .

4. Inspect the fuse. The fuel pump fuse is usually a 20-amp fuse located in the same under-hood fuse box. Check it for a broken element .

Common Symptoms of a Bad Fuel Pump Relay

  • Engine cranks but won’t start. This is the most common symptom. The starter turns the engine over, but no fuel reaches the injectors.
  • No fuel pump noise. You don’t hear the usual humming sound from the rear of the truck when turning the key to “ON.”
  • Intermittent stalling. The truck may start and run fine, then suddenly die while driving. After a few minutes, it may start again.
  • Loss of power. The engine may hesitate or lose power under load, especially when going uphill .

What to Do If the Relay Is Good But the Truck Still Won’t Start

If replacing the relay doesn’t fix the problem, check these components:

Fuel pump fuse. A blown fuse is a common cause. Check the 20-amp fuse in the under-hood fuse box .

Oil pressure safety switch. On many GM trucks, if the fuel pump relay fails, the oil pressure switch can power the pump directly when the engine is running. If both the relay and switch are bad, the pump won’t run .

Fuel pump itself. The pump is located inside the fuel tank. If you have power at the pump connector but the pump doesn’t run, the pump is likely bad. Access the connector through the top of the tank or under the cab .

Ignition switch. A faulty ignition switch can fail to send the “ignition on” signal to the ECM, which then won’t activate the relay .

Where to Buy a Reliable Fuel Pump for Your GMC Sierra

If you have determined that the fuel pump itself needs replacement, you want a part that is durable, reliable, and backed by a solid warranty. That is where KEMSO comes in.

KEMSO Fuel Pumps are high-performance, OEM replacement units designed to meet or exceed factory specifications. Whether you drive a 1998 Sierra with a 5.7L Vortec or a 2020 Sierra with the 5.3L EcoTec3, KEMSO offers a direct-fit solution. Every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind that your repair will last.

Visit KEMSO Racing today to find the exact fuel pump for your GMC Sierra: https://www.kemsoracing.com/

Final Thoughts

Locating the fuel pump relay on your GMC Sierra is straightforward once you know where to look. For most models, it is in the under-hood fuse box on the driver’s side. Always check the relay first—it is a cheap and easy fix. If the relay is good, move on to the fuse, the oil pressure switch, and finally the pump itself.

For a replacement fuel pump that you can trust, choose KEMSO. With high-quality construction, OEM-level fit, and a lifetime warranty, KEMSO is the smart choice for getting your GMC Sierra back on the road.

For the best fuel pump for your GMC Sierra, visit: https://www.kemsoracing.com/


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