2004 Silverado Fuel Pump Relay Location: Quick Guide to Finding and Fixing It

The fuel pump relay on a 2004 Chevy Silverado 1500 is located in the under-hood fuse block, which sits on the driver's side of the engine compartment near the battery. The relay is clearly labeled "FUEL PUMP" or "F/P" on the fuse box lid diagram. There is no physical reset switch on this truck — the relay and fuse are the only components you need to check for a no-start condition related to fuel delivery.

If your Silverado cranks but won't start, the fuel pump relay is the first thing to check. It fails more often than the pump itself, especially on trucks with over 120,000 miles that have spent summers baking in the engine bay. The good news is that testing and replacing the relay takes about 30 seconds and costs between $6 and $15.

Where Exactly Is the Fuel Pump Relay?

The under-hood fuse box on a 2004 Silverado 1500 is a black plastic box located on the driver's side of the engine compartment, right next to the battery. To access the relay:

  1. Open the hood and locate the black fuse box near the battery.
  2. Lift the cover by pulling the tab — the fuse box diagram is printed on the inside of the lid.
  3. Look for the relay labeled "FUEL PUMP" or "F/P" — it sits in one of the standard relay slots.

The fuel pump relay on the 2004 model is a standard 5-pin ISO mini-relay. Common replacement part numbers include GM 15321059, AC Delco D1750C, and Standard Motor Products RY-601 — any of these will work on any Silverado from 1999 through 2024.

How to Test the Fuel Pump Relay in Under 5 Minutes

You don't need any special tools to test the relay. Here's the quick swap method that works every time:

Step 1: Turn the key to the RUN position (do not start the engine). Listen near the fuel tank — you should hear a 2-second humming sound as the fuel pump primes. If you hear nothing, the pump is not getting power.

Step 2: Open the under-hood fuse box. Locate the fuel pump relay. Pull it straight out using your fingers or a pair of needle-nose pliers.

Step 3: Swap the fuel pump relay with an identical relay from another slot. Good candidates are the A/C compressor relay or the horn relay — they have the same pin layout.

Step 4: Try to start the truck. If it starts after the swap, the fuel pump relay was bad. Keep the swapped relay in place and buy a new one for the slot you borrowed from.

This test works because if the relay is the problem, swapping in a known-good relay from another circuit will immediately restore power to the fuel pump. This is the most common fix — about 80% of no-start cases on Silverados are traced back to a bad relay, not a bad pump.

The Fuel Pump Fuse: Your Second Check

If the relay swap didn't fix the problem, check the fuel pump fuse. On the 2004 Silverado, this is a 20-amp MINI fuse located in the same under-hood fuse block. It's labeled "FUEL PUMP" or "F/PMP" on the diagram.

To test the fuse:

  1. Use the fuse puller tool found inside the fuse box cover.
  2. Hold the fuse up to the light. If the metal strip inside is broken or melted, the fuse is blown.
  3. If you have a multimeter, set it to continuity mode and touch the two small metal prongs on top of the fuse. A beep means the fuse is good; no reading means it's blown.

Never replace a blown fuse with a higher-amp fuse. Using a 25-amp or 30-amp fuse where a 20-amp belongs can damage the wiring or cause a fire. If the new fuse blows immediately, you have a short circuit somewhere in the fuel pump wiring or the pump itself — that requires further diagnosis.

When the Relay and Fuse Are Fine But the Pump Still Doesn't Run

If both the relay and fuse test good, the problem is likely the fuel pump itself. Before dropping the fuel tank, do two more checks:

Listen for the prime cycle. Turn the key to RUN with the windows down and radio off. You should hear a 2-second whir from the rear of the truck near the fuel tank. No sound means the pump is dead or not receiving power.

Perform a fuel pressure test. This is the most reliable way to confirm pump failure. Connect a fuel pressure gauge to the test port on the fuel rail (located on the engine). Turn the key to RUN. For a 2004 Silverado 1500, fuel pressure should read between 55 and 62 psi. If the pressure reads zero or stays well below spec, the fuel pump is failing or has failed completely.

Common symptoms of a failing fuel pump on your Silverado include:

  1. Whining noise from the fuel tank — a loud, high-pitched hum from the rear of the truck is a classic sign of a pump wearing out.
  2. Hard starting when warm — if the engine cranks fine but struggles to start after it has been driven and warmed up, the pump may be losing prime.
  3. Loss of power under load — if the truck feels sluggish when towing, climbing a hill, or accelerating hard, the pump may not be delivering enough fuel pressure.
  4. Sputtering or surging — the engine may hesitate or surge at highway speeds, especially when the fuel level is low.
  5. Stalling and no-start — in the worst case, the pump stops working entirely, and the engine will not start.

The Fuel Pump Itself: Location and Replacement

The fuel pump on the 2004 Silverado 1500 is located inside the fuel tank, under the rear of the truck on the driver's side. This in-tank design protects the pump from external damage and keeps it cool, which extends its life. Accessing the pump requires removing the fuel tank — there is no access panel under the rear seat on this model.

In the 2004 Silverado, the fuel pump is part of a complete module assembly that includes the pump, sending unit, float assembly, and often the fuel pressure regulator. When the pump fails, replacing the entire module is recommended rather than swapping just the pump motor into the old housing. This avoids leaks, faulty fuel gauge readings, and the need to drop the tank again soon after.

The fuel pump on a 2004 Silverado typically lasts 100,000 to 150,000 miles, though some last up to 200,000 miles with proper maintenance. Running the tank below a quarter full regularly will shorten the pump's life dramatically, as the fuel helps cool and lubricate the pump.

Diagnosing Without Dropping the Tank

Before you commit to a fuel tank removal, run through this quick checklist in order:

  1. Check the fuel pump relay — swap it with the A/C or horn relay. Costs nothing and takes 30 seconds.
  2. Check the fuel pump fuse — inspect the 20-amp fuse for a broken element.
  3. Listen for the prime — turn the key to RUN and listen at the filler neck for a 2-second hum.
  4. Test fuel pressure — connect a gauge to the fuel rail test port. Target is 55–62 psi.
  5. Check for power at the pump — if you have a multimeter, you can access the pump connector on top of the fuel tank (requires partially lowering the tank). With the connector disconnected, have a helper turn the key to RUN — you should see 12 volts for about 2 seconds.

If you have power and ground at the pump connector but the pump does not run, the pump is confirmed bad and needs replacement.

Why the 2004 Silverado Fuel Pump Relay Is So Important

The fuel pump relay on your 2004 Silverado is a small component that handles a big job. It acts as a switch controlled by the Powertrain Control Module (PCM). When you turn the key to RUN, the PCM checks engine speed and crankshaft position signals. If everything looks good, the PCM energizes the relay, which sends power from the battery through the fuel pump fuse to the pump.

The relay sits in the under-hood fuse box where it is exposed to engine heat every time you drive. Over time, the internal contacts can wear out or the coil can fail, especially in hot climates. That's why relay failure is so common on Silverados past 120,000 miles — and why checking the relay should always be your first step.

There is no fuel pump reset switch on the 2004 Silverado. Some older vehicles had a physical reset button or inertia switch in the trunk or under the dash, but GM eliminated that setup on the Silverado. The only way to cut power to the pump is through the relay, which the PCM can de-energize if it detects a crash event. If the relay itself fails, the pump simply won't run.

What to Do If You Need to Replace the Fuel Pump

If your diagnosis points to a bad fuel pump, you are looking at replacing the fuel pump module assembly inside the fuel tank. This job requires dropping the fuel tank, which involves:

  1. Draining the fuel tank as much as possible.
  2. Disconnecting the fuel lines and electrical connector.
  3. Supporting the tank and removing the mounting straps.
  4. Lowering the tank from the vehicle.
  5. Removing the lock ring and pulling the fuel pump module out of the tank.
  6. Installing the new module with a new O-ring and lock ring.
  7. Reinstalling the tank and reconnecting everything.

This is a 3- to 5-hour job for a competent DIY mechanic. Before starting, relieve the fuel system pressure by locating the Schrader valve on the fuel rail and pressing the valve stem with the ignition off. Always disconnect the battery to prevent accidental sparks, and work in a well-ventilated area away from any ignition sources.

Recommended: KEMSO Fuel Pump for Your 2004 Silverado

When it is time to replace your Silverado's fuel pump, you want a part that is reliable, durable, and backed by a strong warranty. That is why we recommend KEMSO fuel pumps. KEMSO products are designed as high-performance, OEM replacement units that meet or exceed the original factory specifications for your Silverado. They are built with premium materials for long-lasting durability and undergo rigorous quality testing before leaving the factory. Every KEMSO fuel pump comes with a lifetime warranty, giving you complete peace of mind.

Whether you are hauling equipment to the job site or towing a trailer on the weekend, a KEMSO fuel pump ensures your truck performs reliably mile after mile. Visit the KEMSO website today at https://www.kemsoracing.com/ to find the exact fuel pump for your 2004 Chevy Silverado and take advantage of their lifetime warranty and fast shipping.

Final Summary

Here is what you need to remember about the 2004 Silverado fuel pump relay location:

  1. The relay is in the under-hood fuse box on the driver's side near the battery.
  2. Labeled "FUEL PUMP" or "F/P" on the fuse box lid diagram.
  3. No physical reset switch exists on this model — the relay is the only control component.
  4. Swap test takes 30 seconds — pull the relay and replace it with the A/C or horn relay.
  5. Relay failure is the #1 cause of no-start conditions on Silverados past 120,000 miles.
  6. The fuel pump fuse is also in the same fuse box — it's a 20-amp MINI fuse.

If your 2004 Silverado cranks but won't start, start with the relay. It's the quickest, cheapest, and most likely fix. If the relay and fuse check out, move to the fuel pressure test before dropping the tank. And when replacement is necessary, choose a KEMSO fuel pump for reliable, long-lasting performance backed by a lifetime warranty.

For more information and to find the right fuel pump for your vehicle, visit https://www.kemsoracing.com/ today.


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