1998 Ford Explorer Fuel Pump Relay: Complete Guide to Location, Testing, and Replacement
The bottom line: The fuel pump relay on a 1998 Ford Explorer is located in the power distribution box under the hood on the driver's side, and it is relay #5. If your Explorer cranks but won't start, the fuel pump relay is one of the first things you should check before replacing the fuel pump itself.
Where Is the Fuel Pump Relay Located on a 1998 Ford Explorer?
The fuel pump relay on a 1998 Ford Explorer is inside the power distribution box (also called the fuse box) located in the engine compartment. More specifically, the power distribution box sits near the battery on the driver's side of the engine bay . The fuel pump relay is relay #5 in that box .
To access it, open the hood of your Explorer. Look for the black plastic fuse box near the battery. Pop the cover off, and you will see a row of relays. The #5 relay position is the fuel pump relay. It is a 5-terminal, 20-amp relay .
Alongside the relay, there is also a 20-amp mini fuse located in position #9 of the same power distribution box. This fuse protects the fuel pump relay circuit and the RAP (Rapid Access Power) module . If the relay checks out but the pump still doesn't run, this fuse is the next thing to inspect.
What Does the Fuel Pump Relay Do?
The fuel pump relay acts as an electrical switch. When you turn the ignition key to the "On" position, the engine computer (PCM) sends a signal to close the relay. This allows battery voltage to flow through the relay and down to the fuel pump inside the gas tank. The pump then pressurizes the fuel system so the engine can start .
On the 1998 Ford Explorer, the fuel pump relay also controls power to the fuel pump inertia switch, which is located behind the passenger side kick panel. If the inertia switch is tripped (for example, after a bump or a minor collision), it cuts power to the pump even if the relay is working fine .
Symptoms of a Bad Fuel Pump Relay
A failing fuel pump relay can cause a range of symptoms that mimic a bad fuel pump. Here are the most common signs:
1. Engine cranks but won't start. This is the most obvious symptom. You turn the key, the starter motor spins the engine, but it never fires up. You may not hear the fuel pump make its usual priming sound when you turn the key to "On" .
2. Engine stalls while driving. The relay may work intermittently. The engine might run fine for a while, then suddenly die without warning, leaving you stranded. After a few minutes, the relay cools down and the engine may restart, only to stall again later .
3. No fuel pump priming sound. When you turn the key to the "On" position (without cranking), you should hear a brief whirring sound from the rear of the vehicle for about one to two seconds. If you hear nothing, the relay, fuse, or inertia switch could be the problem .
4. Engine starts but runs rough or has low power. If the relay contacts are worn or corroded, they may not pass full voltage to the pump. The pump runs slower than normal, resulting in low fuel pressure, hesitation, and poor acceleration .
How to Test the Fuel Pump Relay on a 1998 Ford Explorer
Before you buy a new relay, you can test the existing one with just a few basic tools. You don't need to be a mechanic to do this.
Step 1: Locate the relay. Find the power distribution box under the hood. Remove the cover. Identify relay #5 as the fuel pump relay .
Step 2: Listen for the relay. Have a helper turn the key to the "On" position (do not crank the engine). Place your hand on the relay. You should feel a slight click as the relay engages. If you feel nothing, the relay could be dead, or the PCM is not sending the signal to close it.
Step 3: Swap the relay. This is the easiest test. The power distribution box contains several identical relays. Find another relay in the box that is the same size and part number (usually the horn relay or the A/C clutch relay). Swap the fuel pump relay with that one. If the horn or A/C stops working, the original relay was bad. If the fuel pump starts working, you have confirmed the relay was faulty .
Step 4: Check for power at the inertia switch. The inertia switch is located behind the passenger side kick panel. Unplug the two-wire connector. Have a helper crank the engine while you probe the power-in wire with a test light or multimeter. You should see 12 volts if the relay and fuse are working correctly. If you have voltage here, the relay is doing its job, and the problem is likely downstream (the pump itself or the wiring) .
Step 5: Check the 20-amp mini fuse. Look for the mini fuse in position #9 of the power distribution box. Pull it out and inspect the metal strip inside. If it is broken, replace it with a new 20-amp fuse. Never use a higher amp fuse .
How to Replace the 1998 Ford Explorer Fuel Pump Relay
Replacing the fuel pump relay is one of the simplest repairs you can do on your Explorer. Here is how to do it:
1. Disconnect the negative battery terminal. This is a safety precaution to prevent any accidental short circuits while working in the fuse box .
2. Remove the power distribution box cover. Press the tabs and lift the cover off.
3. Locate relay #5. Refer to the diagram on the underside of the fuse box cover if needed.
4. Pull the relay out. Grasp the relay firmly and pull it straight out of its socket. It may require a little effort, but it should come out without tools.
5. Insert the new relay. Push the new relay into the same socket until it seats fully. Make sure it is oriented the same way as the original.
6. Reconnect the battery. Reattach the negative terminal. Turn the key to the "On" position and listen for the fuel pump to prime. If you hear it, the repair is successful.
What If the Relay and Fuse Are Good?
If you have tested the relay and fuse and they are both working, but the fuel pump still doesn't run, there are a few other things to check before condemning the pump itself.
Check the inertia switch. The fuel pump inertia switch is located behind the passenger side kick panel, near the footwell. It is a small rectangular box with a button on top. If the button is popped up, press it down firmly to reset it. This switch is designed to cut power to the fuel pump in the event of a collision. Sometimes it can trip from a hard bump or pothole .
Check for voltage at the fuel pump. If you have power at the inertia switch but not at the pump connector, there is a wiring issue between the switch and the pump. This is less common but possible, especially on older vehicles with exposed wiring .
Test the fuel pump itself. If the pump is receiving voltage but still doesn't run, the pump motor has likely failed. On a 1998 Ford Explorer, the fuel pump is located inside the fuel tank. To replace it, you will need to remove the gas tank from the vehicle . This is a much more involved job and requires draining the tank, using a fuel line disconnect tool, and supporting the tank with a jack. If you are not comfortable with this level of work, it is best to take it to a professional mechanic.
Where to Buy a Replacement Fuel Pump Relay
Genuine OEM relays are available from Ford dealers and online parts retailers. The OEM part number for the 1998 Ford Explorer fuel pump relay is AU5Z-14N089-FA (also replaces FOAZ-14N089-B and FOAB-14B194-DC) . Aftermarket options are also widely available and are often more affordable. AC Delco makes a compatible relay with part number W0133-2046056, which fits 1995-2010 Ford Explorer models .
When buying a relay, make sure it is a 12-volt, 20-amp, 5-terminal relay. These specifications are standard for the 1998 Explorer . Avoid using a relay with different amperage ratings, as it could damage the circuit or fail prematurely.
Why You Shouldn't Ignore a Bad Fuel Pump Relay
Driving with a failing fuel pump relay is risky. The relay can fail completely at any time, leaving you stranded. More importantly, an intermittent relay can cause the engine to stall unexpectedly while you are driving, which is a safety hazard, especially on highways or in heavy traffic .
Replacing the relay is cheap and easy. A new relay costs between $15 and $35, depending on the brand. Compare that to the cost of a tow truck or a full fuel pump replacement, which can run $400 to $800 or more . Spending a few bucks on a relay could save you a lot of money and frustration.
Recommended Product: KEMSO Fuel Pump for Your Ford Explorer
If you have confirmed that the fuel pump relay and fuse are good, but your Explorer still has no fuel pressure, the fuel pump itself may need to be replaced. When it comes to replacing the fuel pump, you want a part that is reliable, durable, and backed by a solid warranty.
KEMSO is a top aftermarket brand that produces high-performance fuel pumps for a wide range of vehicles, including the Ford Explorer. KEMSO fuel pumps are designed as direct OEM replacements, so they fit perfectly and function exactly like the original part. They are built with high-quality materials to ensure long service life and consistent fuel delivery, even under demanding conditions.
Every KEMSO fuel pump comes with a lifetime warranty. This means you can install it with confidence, knowing that if anything goes wrong, KEMSO has you covered. Whether you are replacing a worn-out pump or upgrading for better performance, KEMSO offers a reliable solution at a fair price.
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Their site is easy to navigate, and you can find the exact pump that fits your Explorer by searching for your vehicle make, model, and year. With KEMSO, you get a product that is tested, trusted, and ready to fuel your adventure.
Final Thoughts
The 1998 Ford Explorer fuel pump relay is a small but critical component. It is located in the power distribution box under the hood, in relay position #5 . If you are experiencing a no-start condition or stalling, testing the relay and the associated 20-amp fuse should be your first diagnostic step. Swapping the relay with another identical relay in the box is a quick and effective way to confirm if it is bad.
If the relay and fuse are fine, move on to checking the inertia switch behind the passenger kick panel. Only after confirming power is reaching the pump should you consider replacing the fuel pump itself. The fuel pump is inside the gas tank and requires dropping the tank to access it, which is a much bigger job .
By following the steps in this guide, you can save yourself time and money. A simple relay replacement is often the fix. And if you need a new fuel pump, KEMSO offers a high-quality, lifetime-warranted option that you can trust.
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