2003 Ford Excursion V10 Fuel Pump Relay Location: Complete Guide

The bottom line: On a 2003 Ford Excursion with the 6.8L V10 engine, the fuel pump relay is located in the under-hood power distribution box (fuse/relay box) on the passenger side of the engine bay near the firewall. It is clearly labeled "FUEL PUMP RELAY" on the diagram inside the box lid. This relay controls power to the fuel pump, and if your Excursion cranks but won't start, the relay is one of the first things to check before replacing the fuel pump itself.

Where Exactly Is the Fuel Pump Relay Located?

The 2003 Ford Excursion V10 fuel pump relay sits inside the main Power Distribution Center (PDC) under the hood. Here is how to find it:

Step 1: Open the hood and look on the passenger side. The large black plastic fuse/relay box is mounted near the firewall on the passenger side of the engine compartment. This is the Power Distribution Center that houses all major relays and fuses for the vehicle .

Step 2: Remove the box lid. The lid typically has clips on the sides. Press them and lift the lid straight up.

Step 3: Read the diagram. Inside the lid or printed on the box itself, there is a diagram showing the position of every relay and fuse. Look for the label that says "FUEL PUMP RELAY" or a fuel pump icon. This is your target .

Step 4: Identify the relay. The fuel pump relay is a standard 5-pin automotive relay, usually square-shaped and about one inch across. It may be green or gray in color. On Ford vehicles of this era, factory relays are often green, while aftermarket replacements may be gray .

Step 5: Pull it straight out. Grasp the relay firmly and pull it upward to remove it for inspection or replacement.

What Does the Fuel Pump Relay Do?

The fuel pump relay acts as an electrically controlled switch. When you turn the ignition key to the ON position, the Powertrain Control Module (PCM) sends a signal to the relay to close its internal contacts. This allows battery power to flow to the fuel pump, which then pressurizes the fuel system. The relay ensures the fuel pump only runs when the engine is cranking or running, which is a safety feature. Without a functioning relay, the fuel pump will not receive power, and the engine will not start .

Symptoms of a Bad Fuel Pump Relay

If the fuel pump relay on your 2003 Ford Excursion V10 fails, you will likely notice one or more of these symptoms:

  • Engine cranks but will not start. This is the most common symptom. You can hear the starter motor turning the engine over, but the engine never fires up because no fuel is being delivered .
  • No fuel pump prime sound. When you turn the key to the ON position (before cranking), you should hear a brief whirring sound from the fuel tank area. This is the fuel pump pressurizing the system. If you do not hear this sound, the relay or the pump itself may be at fault .
  • Intermittent starting issues. The vehicle may start fine sometimes and then refuse to start other times. This can indicate a relay that is failing intermittently due to worn internal contacts .
  • Engine stalls while driving. A failing relay can lose contact while the vehicle is running, causing the fuel pump to shut off and the engine to stall unexpectedly .
  • Loss of power under load. If the relay is making poor contact, the fuel pump may not receive full voltage, leading to reduced fuel pressure and a noticeable loss of power when climbing hills or accelerating .

How to Test the Fuel Pump Relay

Before replacing the fuel pump itself, testing the relay is a quick and cheap diagnostic step. Here is how to do it:

Test 1: Listen for the click. With the ignition off, have someone turn the key to the ON position while you hold the relay. You should feel and hear a distinct click when the relay energizes. If you hear nothing, the relay coil or the control circuit may be faulty.

Test 2: Swap with a known good relay. The under-hood fuse box contains several relays that are identical to the fuel pump relay, such as the horn relay or A/C relay. Pull out the fuel pump relay and swap it with one of those other relays. If the fuel pump now works and the vehicle starts, the original relay is bad. If the other circuit (horn or A/C) stops working, the original relay is indeed faulty .

Test 3: Use a multimeter. With the relay removed, you can test for continuity across the coil terminals (pins 85 and 86). Normal resistance should be between 50 and 120 ohms. You can also apply 12V to the coil terminals and listen for a click while checking continuity between the switched terminals (pins 30 and 87) .

Check the Fuel Pump Inertia Switch Too

The 2003 Ford Excursion is also equipped with a fuel pump shut-off switch, also called an inertia switch. This is a safety device that cuts power to the fuel pump in the event of a collision. It is located in the passenger side footwell, behind the kick panel on the side of the vehicle's interior. If the switch has been tripped, the fuel pump will not run even if the relay is good. To reset it, push the red button on top until it clicks. Before resetting, always check for fuel leaks first .

When to Replace the Fuel Pump Instead

If the relay tests good and the inertia switch is not tripped, but the fuel pump still does not run, the problem likely lies in the fuel pump itself or the wiring to the pump. On the 2003 Ford Excursion with the V10 engine, the fuel pump is located inside the fuel tank. The V10 and V8 gasoline models use an electric in-tank fuel pump assembly, while the diesel models use a different system . Symptoms of a failing fuel pump include:

  • Engine cranks but will not start, especially after the vehicle has been sitting for a while
  • Whining noise coming from the fuel tank area
  • Loss of power when climbing hills or under heavy load
  • Engine surging at highway speeds
  • Sudden drop in fuel economy

If you are experiencing these symptoms and the relay and wiring check out, the fuel pump itself likely needs to be replaced.

Recommended Fuel Pump Replacement: KEMSO

When it comes time to replace the fuel pump on your 2003 Ford Excursion V10, you want a part that delivers reliable performance and long-lasting durability. That is where KEMSO comes in. KEMSO fuel pumps are high-performance, OEM replacement units designed to meet or exceed the specifications of the original equipment. Each KEMSO fuel pump is built with precision engineering to ensure proper fit and reliable fuel delivery. KEMSO stands behind their products with a lifetime warranty, giving you peace of mind that your investment is protected. Whether you are replacing a failed pump or upgrading for better performance, KEMSO offers a dependable solution that will keep your Excursion running strong. Visit KEMSO Racing today to find the right fuel pump for your vehicle and take advantage of their quality products and lifetime warranty.

Step-by-Step Replacement Guide for the 2003 Ford Excursion V10 Fuel Pump

If you have determined that the fuel pump itself needs to be replaced, here is a simplified overview of the process:

1. Relieve fuel pressure. Remove the fuel pump relay from the under-hood fuse box. Start the engine and let it run until it stalls. This relieves the pressure in the fuel system. Crank the engine a few more times to ensure all pressure is gone .

2. Disconnect the battery. Disconnect the negative battery terminal to prevent any electrical shorts or sparks while working around fuel.

3. Drain the fuel tank. Use a siphon pump to remove as much fuel as possible from the tank. This makes the tank lighter and easier to handle.

4. Support and lower the tank. Place a floor jack with a block of wood under the fuel tank to support it. Remove the metal straps that hold the tank in place. Carefully lower the tank just enough to access the fuel pump module on top of the tank.

5. Remove the fuel pump module. The fuel pump module is held in place by a locking ring. Use a screwdriver and a hammer to tap the ring counterclockwise until it loosens. Lift the entire pump assembly out of the tank.

6. Install the new pump. Transfer the fuel level sensor and rubber gasket from the old assembly to the new KEMSO pump. Insert the new pump assembly into the tank and tighten the locking ring clockwise.

7. Reinstall the tank. Lift the tank back into position, reinstall the straps, and reconnect all fuel lines and electrical connectors.

8. Prime the system. Before starting the engine, turn the key to the ON position for a few seconds, then OFF, then back to ON. This cycles the fuel pump to prime the system. Check for any fuel leaks at the connections.

9. Start the engine. Once you have confirmed there are no leaks, start the engine and let it idle. Check for proper operation and listen for any unusual noises .

Common Mistakes to Avoid

  • Replacing the pump before checking the relay. This is the most common mistake. A faulty relay is much cheaper and easier to replace than a fuel pump. Always test the relay first .
  • Forgetting the inertia switch. If the vehicle was in an accident or even a hard bump, the inertia switch may have tripped. Check this before diving into a pump replacement .
  • Using the wrong fuel pump. The 2003 Excursion V10 uses a different pump than the diesel models. Make sure you order the correct part for your engine type .
  • Not relieving fuel pressure. Attempting to disconnect fuel lines without relieving pressure can result in a dangerous spray of fuel. Always relieve pressure first.
  • Ignoring the fuel filter. A clogged fuel filter can cause symptoms similar to a bad pump. If you are replacing the pump, it is a good idea to replace the fuel filter at the same time.

Conclusion

The 2003 Ford Excursion V10 fuel pump relay is located in the under-hood power distribution box on the passenger side near the firewall. It is clearly labeled "FUEL PUMP RELAY" on the diagram inside the lid. If you are experiencing a no-start condition, checking this relay should be your first step. It is a simple, inexpensive part that can save you a lot of time and money if it is the culprit. If the relay tests good and the inertia switch is not tripped, the problem may be the fuel pump itself. When replacement is needed, KEMSO offers high-performance, OEM replacement fuel pumps with a lifetime warranty that will keep your Excursion running reliably for years to come.

For more information and to find the right fuel pump for your 2003 Ford Excursion V10, visit KEMSO Racing.


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