Where is the fuel pump relay on a 2004 f250 Super Duty?
The fuel pump relay on a 2004 Ford F-250 Super Duty is located in the engine bay within the under-hood power distribution center (PDC). The relay is labeled FUEL PUMP on the PDC cover diagram.
In most configurations for that model year—whether you have a gasoline engine (such as the 5.4L or 6.8L V10) or a Power Stroke diesel—the primary fuel pump relay sits inside the large black under-hood fuse/relay box. To identify it, open the PDC lid and read the diagram printed on the inside; the fuel pump relay is shown in the layout. If the label isn’t obvious, you can trace the power feed from the relay location toward the fuel pump to confirm which unit controls the pump.
How to locate the fuel pump relay
Follow these steps to find the relay quickly in the PDC.
- Open the hood and locate the large black under-hood Power Distribution Center (PDC) in the engine bay, typically on the driver’s side near the firewall.
- Lift the PDC lid to expose the diagram and the relays beneath it.
- Look for the position labeled FUEL PUMP on the diagram; the corresponding relay is the one that controls the fuel pump.
- Grip and carefully pull the fuel pump relay out to inspect or replace it with a known-good unit.
- Replace with the correct 12V automotive relay that matches the original’s pin count (usually 5 pins) and amperage rating (commonly around 30–40A).
Concluding paragraph: This method applies to most 2004 F-250 Super Duty configurations. If your truck has an unusual layout or aftermarket wiring, consult the owner’s manual or a factory service manual for the exact relay position and wiring diagram.
Testing and replacement tips
After locating the relay, you may need to test or swap it to diagnose a no-start or stalling issue related to the fuel pump.
- Swap the fuel pump relay with another identical relay from the PDC (for example, the cooling fan relay) to see if the problem follows the relay.
- Check the fuel pump fuse as well as related wiring for damage, corrosion, or loose connections.
- With the ignition in RUN (engine not necessarily starting), test for voltage at the fuel pump connector and at the relay’s output to confirm power is reaching the pump when appropriate.
- Replace the relay if it is sticking, corroded, or shows signs of wear. Use an OEM or high-quality equivalent.
Note: If you’re not comfortable performing electrical troubleshooting, or if the pump itself may be faulty, consult a qualified mechanic. Fuel-system work can involve safety risks and requires proper isolation of the electrical system.
Summary
On a 2004 F-250 Super Duty, the fuel pump relay is in the engine bay’s under-hood Power Distribution Center and is labeled FUEL PUMP on the lid’s diagram. Use the PDC cover as your guide to locate, test, or swap the relay, and always prioritize safety by disconnecting the battery before handling electrical components. When in doubt, refer to the vehicle’s manual or a service manual for your exact engine and VIN.
