2004 Nissan Xterra Fuel Pump Relay: Location, Symptoms, and Step-by-Step Replacement

The 2004 Nissan Xterra fuel pump relay is located in the interior fuse box, mounted behind the lower cover on the driver's side of the dashboard, just left of the steering column. If your Xterra cranks but will not start, and you cannot hear a 2–3 second hum from the fuel tank when you turn the key to the ON position, the fuel pump relay is one of the first components you should check . The fuel pump relay is a small, inexpensive electrical switch that sends power to the fuel pump when the ignition is turned on. When this relay fails, the fuel pump receives no power, the fuel rail builds no pressure, and the engine will not fire. This guide walks you through the symptoms, the exact relay location for a first-generation (2000–2004) Xterra, how to test the relay, how to replace it, and when the problem may actually be something else entirely.

What Does the Fuel Pump Relay Do?

Before you start digging into the dashboard, it helps to understand what the relay actually does. The fuel pump relay is an electromagnetic switch that controls the flow of electrical power to the fuel pump. When you turn the ignition key to the ON position, the Engine Control Module (ECM) energizes the relay coil, which closes the internal contacts and sends battery voltage to the fuel pump . The pump then primes the fuel system for about 5 seconds, building pressure so the engine can start . Once the engine is running, the relay continues to supply power as long as the ignition is on.

A failed relay interrupts this power path. The engine will still crank over because the starter circuit is separate, but it will not start because there is no fuel pressure . The fuel pump relay is a common failure point on first-generation Xterras, especially as the vehicle ages and the relay contacts wear out from years of use.

Symptoms of a Bad Fuel Pump Relay

A faulty fuel pump relay can produce several noticeable symptoms. Recognizing them early can save you from being stranded.

1. Engine Cranks but Won't Start: This is the most common symptom. You turn the key, the starter spins the engine, but it never fires up . If the relay has failed completely, the fuel pump never gets power, so there is no fuel pressure at the injectors.

2. No Fuel Pump Priming Sound: When you turn the key to the ON position (without cranking), you should hear a faint whirring or humming sound coming from the rear of the vehicle near the fuel tank. This is the fuel pump priming the system. If you hear nothing, the pump is not receiving power, and the relay is a likely suspect .

3. Engine Starts Then Dies Immediately: In some cases, a failing relay may allow the pump to run briefly, then cut power. The engine will start for a second or two and then stall. This happens when the relay contacts are worn and cannot maintain a solid connection .

4. Intermittent Starting Problems: If the relay is failing intermittently, you may experience random no-start conditions. The Xterra may start fine one day and refuse to start the next. This is often caused by internal relay contacts that are pitted or corroded.

5. Engine Stalls While Driving: Though less common with a relay failure, a complete loss of power to the fuel pump while driving will cause the engine to stall suddenly. If the relay dies mid-drive, the engine will shut off and will not restart .

Where Is the Fuel Pump Relay on a 2004 Nissan Xterra?

On the 2004 Nissan Xterra (first generation, 2000–2004), the fuel pump relay is located in the interior fuse box, which is mounted under the dashboard on the driver's side, behind a lower cover. The relay is in slot 1 of that fuse box, and it is a 15A relay . Some sources also describe it as being on a bracket near the data link connector, accessible without removing the entire lower dash panel .

To access the relay, follow these steps:

1. Sit in the driver's seat and look under the dashboard, to the left of the steering column.
2. You will see a plastic cover or panel. On some models, there is a small fuse box cover that you can pull straight off by hand . On others, you may need to remove a lower dash trim panel held in place by a few screws or clips.
3. Once the cover is removed, you will see a fuse and relay block. The fuel pump relay is in position 1, which is the first slot .
4. The relay is a small, rectangular black component that plugs directly into the fuse box. It should pull straight out with a firm tug.

If you are having trouble seeing the relay, use a flashlight. The label on the back of the fuse box cover often lists the component for each slot, which can help you confirm you are looking at the right relay .

How to Test the Fuel Pump Relay

Before you buy a new relay, it is smart to test the existing one. There are two methods: a simple swap test and a bench test with a multimeter.

Method 1: The Swap Test

This is the fastest and easiest way to check if the relay is the problem.

1. Locate the fuel pump relay in the driver's side fuse box .
2. Find another relay in the same fuse box that has the same part number or the same physical size and pin layout. The horn relay or the rear window defogger relay are often identical .
3. Pull out the fuel pump relay and push in the known-good relay in its place.
4. Turn the key to the ON position and listen for the fuel pump prime sound.
5. If you now hear the pump, your original relay was bad. If you still hear nothing, the problem is elsewhere .

Method 2: Bench Test with a Multimeter

If you have a digital multimeter, you can test the relay directly.

1. Remove the relay from the fuse box.
2. Set your multimeter to measure resistance (ohms).
3. The relay will have four or five terminals. Typically, terminals 3 and 5 are the switched contacts, and terminals 1 and 2 are the coil .
4. Check continuity between terminals 3 and 5. There should be no continuity (infinite resistance) when the relay is at rest.
5. Apply 12V battery power to the coil terminals (1 and 2). You should hear a click, and now continuity should exist between terminals 3 and 5 .
6. If the relay does not click, or if the contacts do not close, the relay is bad and needs replacement.

Step-by-Step Fuel Pump Relay Replacement

Replacing the fuel pump relay on a 2004 Xterra is a simple DIY job that takes about five minutes. No tools are required, other than possibly a flathead screwdriver to pop off the lower dash cover.

1. Turn the ignition off and remove the key from the ignition switch.
2. Remove the lower dash cover on the driver's side to expose the fuse box .
3. Locate the fuel pump relay in slot 1 of the fuse box .
4. Pull the relay straight out of the socket with a firm, steady tug. If it is tight, gently rock it side to side.
5. Compare the new relay to the old one to confirm they are identical.
6. Push the new relay firmly into the socket until it seats fully. You should feel a slight click.
7. Reinstall the dash cover and turn the key to the ON position.
8. Listen for the fuel pump prime sound from the rear of the vehicle. If you hear it, the replacement was successful.
9. Start the engine to confirm everything is working.

What If the New Relay Doesn't Fix the Problem?

If you have replaced the relay and the fuel pump still does not turn on, the problem may lie elsewhere in the fuel pump circuit. Work through these checks in order.

1. Check the Fuel Pump Fuse: The fuse box also contains a fuse that protects the fuel pump circuit. On first-generation Xterras, this is a 15A fuse in the same interior fuse box, in slot 1 alongside the relay . Pull the fuse and inspect the metal band inside. If it is broken, the fuse is blown. Replace it with a new fuse of the same amperage. If it blows again, you have a short circuit that needs further investigation .

2. Check the Fuel Pump Relay Power Supply: With the relay removed, turn the ignition to ON and use a multimeter to check for battery voltage at terminals 2 and 5 of the relay socket. If there is no voltage, the problem is a blown fuse or a wiring issue between the fuse block and the relay .

3. Check the Wiring to the Fuel Pump: The fuel pump is located inside the fuel tank. There is a harness connector near the fuel tank that carries power and ground to the pump. Check this connector for corrosion, loose pins, or damaged wires .

4. Test the Fuel Pump Itself: If the relay is good, the fuse is good, and the wiring checks out, the fuel pump itself may be dead. You can test the pump by applying 12V directly to the pump connector and listening for it to spin. If it does not, the pump needs replacement .

5. Check the ECM Signal: The ECM sends a ground signal to terminal 1 of the relay to energize the coil. If the ECM is not sending this signal, the relay will not click. This can happen after the vehicle runs out of gas, which can sometimes trigger an ECM fault. Check for continuity between the ECM connector and the relay socket per the wiring diagram .

A Cautionary Note About Running Out of Gas

Several owners have reported that their Xterra fuel pump failed or stopped working after the vehicle ran out of gas . Running a fuel tank dry can overheat the fuel pump because the fuel itself acts as a coolant. It can also suck debris and sediment from the bottom of the tank into the pump, causing it to seize. If your Xterra stalled after running out of fuel and now will not restart, the fuel pump may have failed internally. Even if the relay and fuse are good, a dead pump will produce a no-start condition .

Fuel Pressure Specifications for the 2004 Xterra

If you want to verify whether the fuel system is building pressure, connect a fuel pressure gauge to the Schrader valve on the fuel rail. For the 2004 Xterra with the 3.3L V6 engine, the specification is about 34 psi at idle and about 43 psi with the vacuum line disconnected from the fuel pressure regulator . If the pressure reads zero or is well below spec, fuel delivery is the problem. If the pressure is within spec but the engine still will not start, the issue is likely in the ignition system .

When the Relay Is Good but the Pump Is Bad

If you have confirmed that the relay clicks, the fuse is intact, and power is reaching the fuel pump connector, the pump itself is likely the culprit. Replacing the fuel pump on a 2004 Xterra is a more involved job because the pump is located inside the fuel tank. You will need to either drop the fuel tank or remove the truck bed to access it . This job requires basic hand tools, a fuel line disconnect tool, jack stands, and a drain pan. If you are not comfortable working with fuel systems, this is a job best left to a professional mechanic.

Recommended Fuel Pump Upgrade: KEMSO

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Final Thoughts

A dead fuel pump relay is one of the most common reasons a 2004 Nissan Xterra cranks but will not start. The relay is easy to access on the driver's side of the dashboard, and replacing it takes only minutes. Start by listening for the fuel pump prime sound when you turn the key to ON. If you hear nothing, check the relay in slot 1 of the interior fuse box, swap it with a known-good relay, and see if that resolves the issue . If the relay is fine, move on to checking the fuse, the wiring, and finally the pump itself. With a little patience and basic troubleshooting, you can get your Xterra back on the road without a trip to the shop.

For a reliable replacement fuel pump with a lifetime warranty, visit https://www.kemsoracing.com/ and find the right KEMSO pump for your 2004 Nissan Xterra.