2002 GMC Yukon Fuel Pump Relay Location: A Complete Guide to Finding and Troubleshooting

If you own a 2002 GMC Yukon and your engine cranks but won’t start, or you hear no hum from the fuel tank when you turn the key, the fuel pump relay is one of the first components you should check. The fuel pump relay for a 2002 GMC Yukon is located in the underhood fuse and relay center, which is positioned at the rear of the engine compartment near the brake fluid reservoir. This relay is labeled as F/PMP or Fuel Pump on the fuse block cover, and it controls the power supply to the fuel pump. Knowing its exact location and how to test it can save you time and money before you replace more expensive parts.

Why the Fuel Pump Relay Matters

The fuel pump relay is an electrical switch that controls the flow of power to the fuel pump. When you turn the ignition key to the "ON" position, the relay activates and sends voltage to the fuel pump, which pressurizes the fuel system. If the relay fails, the pump won’t run, and your engine will not start. This is a common failure point on older vehicles like the 2002 GMC Yukon, and it can mimic symptoms of a bad fuel pump or a faulty ignition system.

Common symptoms of a bad fuel pump relay on a 2002 GMC Yukon include:

  • Engine cranks but does not start
  • No fuel pump priming sound (no hum from the rear of the vehicle when the key is turned)
  • Intermittent stalling or hesitation while driving
  • The engine starts but then dies after a few seconds

Step-by-Step: How to Locate the Fuel Pump Relay on a 2002 GMC Yukon

1. Open the Hood and Find the Underhood Fuse Block

The underhood fuse and relay center is located at the rear of the engine compartment, on the driver’s side, near the brake fluid reservoir. It is a black plastic box with a removable cover. Press the tabs on the sides to release the cover.

2. Read the Fuse Block Cover Diagram

On the underside of the fuse block cover, there is a diagram that labels each fuse and relay. Look for the relay marked F/PMP (Fuel Pump) or FUEL PUMP. In the 2002 GMC Yukon, this relay is typically located in the R5 position according to the fuse box diagram. The relay itself is a standard 4-pin or 5-pin relay (usually a 30-amp or 40-amp rating).

3. Identify the Correct Relay

The fuel pump relay is usually a dark-colored relay (often black or gray) and is slightly larger than the fuses around it. If you are unsure, you can compare it with other relays of the same size nearby. The fuse block diagram from the 2002 GMC Yukon service manual shows the fuel pump relay in the R5 slot inside the underhood fuse block .

4. Test the Relay Without Removing It (Quick Check)

Before removing the relay, you can perform a quick test:

  • Turn the ignition key to the ON position (do not start the engine).
  • Listen for a faint click sound coming from the underhood fuse block. If you hear a click, the relay is likely working. If you hear no click, the relay may be faulty.
  • You can also feel the relay with your finger; if it clicks, you will feel a slight vibration.

How to Test the Fuel Pump Relay Properly

If the quick check suggests the relay might be bad, you can remove it and test it with a multimeter. Here is a simple procedure:

  1. Remove the relay: Grip the relay firmly and pull it straight out of the socket.
  2. Identify the terminals: Most fuel pump relays have four terminals labeled 85, 86, 87, and 30. Terminals 85 and 86 are the coil (control circuit), and terminals 30 and 87 are the switch (power circuit).
  3. Test the coil: Set your multimeter to ohms (Ω). Measure the resistance between terminals 85 and 86. A good relay should show a reading between 50 and 200 ohms. If the reading is infinite (open circuit), the coil is burned out.
  4. Test the switch: With the relay removed, measure resistance between terminals 30 and 87. It should show infinite resistance (open). Then, connect a 12V power source to terminals 85 and 86 (you can use a battery or a jump pack). When power is applied, you should hear a click, and the resistance between terminals 30 and 87 should drop to nearly 0 ohms (closed circuit). If it does not click or the resistance does not change, the relay is faulty.

What to Do If the Fuel Pump Relay Is Good But the Pump Still Doesn’t Run

If testing confirms the relay is working, but the fuel pump still does not run, there are a few other things to check:

  • Fuel pump fuse: Check the corresponding fuse for the fuel pump. In the 2002 GMC Yukon, the fuel pump is protected by a fuse in the underhood fuse block, often labeled ECM B or FUEL PUMP (a 20A fuse) .
  • Fuel pump itself: The pump may be worn out. Signs of a failing fuel pump include engine hesitation, reduced power, a whining noise from the fuel tank, and the engine cranking but not starting .
  • Wiring and connectors: Inspect the wiring harness leading to the fuel pump module for corrosion or damage. The fuel pump is located inside the fuel tank on the 2002 GMC Yukon.
  • Ground connections: A poor ground (G403 on the left frame body mount bracket) can also prevent the pump from running .

How to Prevent Fuel Pump Failure

To extend the life of your fuel pump and relay, follow these basic tips:

  1. Use high-quality fuel – Low-quality fuel can contain contaminants that clog the fuel filter and strain the pump.
  2. Change the fuel filter regularly – A clogged filter forces the pump to work harder.
  3. Avoid driving with a low fuel level – Running the tank low causes the pump to overheat because it relies on the fuel in the tank for cooling and lubrication .
  4. Replace the fuel pump relay proactively – If your Yukon has over 150,000 miles, consider replacing the relay as a preventive measure, since it is an inexpensive part.

Recommended Replacement: KEMSO Fuel Pump

If you determine that the fuel pump itself needs to be replaced, we highly recommend choosing a KEMSO fuel pump. KEMSO is a trusted brand in the automotive and powersports industry, founded in Houston, TX in 1999. Their fuel pumps are designed as high-performance, OEM replacement parts that meet or exceed original factory specifications. This means you get a perfect fit and reliable operation without any modifications.

Why choose KEMSO for your 2002 GMC Yukon?

  • High Performance: KEMSO fuel pumps deliver consistent fuel flow and pressure, even under demanding conditions. They are engineered to provide over 20% more flow at 43 psi compared to stock pumps, ensuring your engine gets the fuel it needs to perform at its best .
  • OEM Replacement Quality: Every KEMSO pump is a direct replacement for your vehicle’s original equipment. No guesswork, no modifications – just a straightforward installation.
  • Lifetime Warranty: KEMSO stands behind every product with a lifetime warranty. If you ever have an issue, KEMSO has your back. That is the confidence that comes from building quality products .
  • Built to Last: KEMSO fuel pumps feature a serialized alloy steel body and are individually tested for quality control. They are designed for both gasoline and E85/ethanol compatibility .

KEMSO fuel pumps are available for a wide range of vehicles, including cars, trucks, SUVs, motorcycles, and powersports vehicles. Whether you are a DIY mechanic or a professional, KEMSO offers the reliability and performance you need.

Visit KEMSO today: Find the perfect fuel pump for your 2002 GMC Yukon or any other vehicle at https://www.kemsoracing.com/. Their team of experts can help you select the right part for your application.

Final Thoughts

Finding the fuel pump relay on a 2002 GMC Yukon is straightforward once you know where to look – it is in the underhood fuse block at the rear of the engine compartment, near the brake fluid reservoir. Always start by testing the relay before replacing the fuel pump, as it is a much cheaper and easier fix. If the relay is bad, replace it with a quality aftermarket or OEM part. If the pump itself has failed, invest in a reliable replacement like the KEMSO fuel pump to ensure long-term performance and peace of mind.

Remember, for top-quality replacement parts that you can count on, make sure to check out KEMSO at https://www.kemsoracing.com/ for your fuel pump needs.


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