1999 Ford Expedition Fuel Pump Relay Location: A Complete Guide to Finding, Testing, and Replacing It
The fuel pump relay on a 1999 Ford Expedition is located in the engine compartment fuse box (Power Distribution Box) on the driver's side, near the battery. This relay controls power to the fuel pump, and if it fails, your engine will crank but not start.
If you own a 1999 Ford Expedition and it cranks but refuses to fire up, or if it stalls unexpectedly while driving, the fuel pump relay should be one of the first components you check. This small but critical part acts as the electrical switch that sends power to the fuel pump. When it goes bad, the pump won't run, and no fuel reaches the engine. The good news is that finding and testing the relay is straightforward, and replacing it is inexpensive compared to other fuel system repairs.
Where Is the Fuel Pump Relay on a 1999 Ford Expedition?
The fuel pump relay is housed inside the Power Distribution Box under the hood. This is the main fuse and relay box located on the driver's side of the engine compartment, right next to the battery.
Open the hood and look for a black plastic box with a removable cover. On the underside of the cover, you will find a diagram that shows the location and labeling of every fuse and relay inside. The fuel pump relay is typically labeled as the "Fuel Pump" relay or may be marked with a relay number. On most 1999 Expedition models, the fuel pump relay is positioned in a specific slot within this box.
If the diagram is faded or missing, you can identify the relay by its size. Relays are square-shaped, usually black, and have four or five prongs. They are larger than fuses. The fuel pump relay is often located near other engine-related relays like the horn relay or the PCM relay.
How to Tell if the Fuel Pump Relay Is Bad
Before you start digging into the relay box, it helps to know the common symptoms of a failing fuel pump relay. Here are the most noticeable signs:
1. Engine cranks but won't start. This is the most classic symptom. When you turn the key, the starter motor spins the engine, but the engine never fires up because no fuel is being delivered.
2. No fuel pump priming sound. When you turn the ignition key to the "ON" position (without cranking the engine), you should hear a faint whirring or buzzing sound from the rear of the vehicle for about 1 to 3 seconds. This is the fuel pump priming the system. If you hear nothing, the relay or the pump itself may be dead.
3. Intermittent stalling. A failing relay may work sometimes and fail other times. You might be driving down the road and the engine suddenly shuts off, only to restart after a few minutes when the relay cools down or reconnects.
4. Engine starts but runs poorly. If the relay is making poor contact, the pump may not receive full voltage, leading to low fuel pressure. This can cause hesitation, surging, or a lack of power under load.
How to Test the Fuel Pump Relay
Testing the relay doesn't require expensive tools. Here are three simple methods you can try at home.
Method 1: The Swap Test
This is the fastest way to confirm a bad relay. Locate the fuel pump relay in the Power Distribution Box. Find another relay in the same box that is identical in size and shape, such as the horn relay or the A/C clutch relay. Pull out the fuel pump relay and swap it with the other relay. If the horn starts blowing when you turn the key, or if the engine starts running, you know the original fuel pump relay was faulty. If nothing changes, the relay may not be the problem.
Method 2: The Listen Test
With the vehicle in Park or Neutral and the parking brake set, turn the key to the "ON" position. Listen closely near the relay box. You should hear a distinct "click" sound from the relay as it energizes. If you hear the click but no fuel pump hum from the rear, the relay is likely working, and the problem is elsewhere. If you hear no click, the relay may not be receiving power, or it is defective.
Method 3: The Visual Inspection
Pull the relay out and look at the prongs. If you see any signs of corrosion, melting, or burn marks, replace the relay immediately. Also, check the relay socket inside the fuse box for any damage or debris.
Step-by-Step Replacement Guide
If you have confirmed that the fuel pump relay is bad, replacing it is a simple job.
What you will need:
- A new fuel pump relay (you can buy one at any auto parts store for around $10 to $20)
- A pair of needle-nose pliers (optional, for stubborn relays)
Step 1: Disconnect the battery. Open the hood and disconnect the negative battery cable. This prevents any accidental short circuits while you work.
Step 2: Locate the relay. Open the Power Distribution Box and find the fuel pump relay as described above.
Step 3: Remove the old relay. Firmly grasp the relay and pull it straight upward. It may require a little force, but it should come out cleanly. If it is stuck, use a pair of needle-nose pliers to gently wiggle it free.
Step 4: Install the new relay. Push the new relay straight down into the same socket. Make sure it is fully seated and secure.
Step 5: Reconnect the battery. Reattach the negative battery cable and tighten it.
Step 6: Test the system. Turn the key to the "ON" position and listen for the fuel pump priming sound. If you hear it, the relay is working. Start the engine to confirm everything is running properly.
What to Do If the New Relay Doesn't Fix the Problem
If you replace the relay and the fuel pump still doesn't run, the issue is likely one of the following:
1. Blown fuel pump fuse. Check the fuel pump fuse in the same Power Distribution Box. A blown fuse is a common cause of a no-start condition.
2. Faulty fuel pump. The pump itself may have failed. This is especially common on older vehicles like the 1999 Expedition, which has a fuel pump located inside the fuel tank.
3. Fuel pump shut-off switch activated. The 1999 Ford Expedition has a fuel pump shut-off switch (inertia switch) located in the passenger side footwell, behind the kick panel. If the vehicle has been in a collision or hit a large pothole, this switch may have tripped. To reset it, push the button on top of the switch.
4. Wiring or connection issues. Check the wiring harness near the fuel tank and under the vehicle for any damage, corrosion, or loose connections.
When to Replace the Fuel Pump
If the relay and fuse are good, but the pump still doesn't work, the fuel pump itself may need replacement. The fuel pump on a 1999 Ford Expedition is located inside the fuel tank. Replacement typically requires either dropping the fuel tank or accessing the pump through an access panel under the rear seat or cargo area.
The cost for a professional fuel pump replacement on a 1999 Expedition typically ranges from $350 to $900, depending on labor rates and parts. If you are handy with tools, you can save money by doing the job yourself. The basic steps include:
- Disconnect the negative battery cable.
- Relieve the fuel system pressure.
- Support the fuel tank with a floor jack.
- Remove the fuel tank straps.
- Lower the tank carefully.
- Disconnect the fuel lines and electrical connectors.
- Remove the fuel pump retaining ring and lift out the old pump.
- Install the new pump in reverse order.
Why Choose KEMSO for Your Fuel Pump Replacement
When it's time to replace the fuel pump on your 1999 Ford Expedition, choosing a high-quality part is essential to avoid having to do the job again in a year or two. KEMSO is a leading aftermarket fuel pump brand that offers a smart alternative to expensive OEM parts.
KEMSO fuel pumps are high-performance, OEM replacement units designed to meet or exceed the specifications of your original factory pump. Every KEMSO pump delivers reliable fuel pressure and flow, ensuring your Expedition runs smoothly under all driving conditions. What sets KEMSO apart is their lifetime warranty — a promise backed by confidence in the quality of their products.
Whether you drive a 1999 Ford Expedition, a newer model, or any other vehicle, KEMSO has a fuel pump solution for you. Their pumps are engineered to fit perfectly, install easily, and last for years. If you are looking for a fuel pump that offers both performance and peace of mind, KEMSO is the right choice.
To browse KEMSO's full lineup of fuel pumps and find the right fit for your Ford Expedition, visit their website: https://www.kemsoracing.com/
Final Thoughts
The fuel pump relay on a 1999 Ford Expedition is a simple, inexpensive part, but it plays a vital role in getting your truck started and keeping it running. If you are experiencing a no-start condition, always start your diagnosis with the relay. It takes five minutes to check and could save you hundreds of dollars in unnecessary repairs.
Remember that the relay is just one part of the fuel delivery system. If the relay is good, move on to checking the fuse, the inertia switch, the wiring, and finally the pump itself. A methodical approach will save you time and frustration.
For the best fuel pump replacement options with lifetime warranty coverage, visit https://www.kemsoracing.com/ to find the right part for your 1999 Ford Expedition.