1999 Ford F150 Fuel Pump Relay Location: Complete Guide to Finding and Replacing It

If you own a 1999 Ford F-150 and are experiencing starting issues, the fuel pump relay is often the first component to check. The fuel pump relay on a 1999 Ford F-150 is located in the under-hood power distribution box (fuse box) on the driver’s side of the engine compartment, near the firewall. It is labeled as relay position 301 or marked “Fuel Pump Relay” on the diagram inside the fuse box lid. This relay controls power to the fuel pump, and when it fails, the engine won’t start or may stall intermittently.

What Does the Fuel Pump Relay Do?

The fuel pump relay is an electromagnetic switch that acts as a bridge between the battery and the fuel pump. When you turn the ignition key, the Powertrain Control Module (PCM) sends a signal to the relay, which then closes and allows power to flow to the fuel pump. The pump only runs when the engine needs fuel, such as during starting and running conditions. Without a working relay, the fuel pump won’t receive power, and the engine will crank but not start.

Exact Location of the 1999 Ford F-150 Fuel Pump Relay

Step 1: Open the hood and look on the driver’s side of the engine compartment. You will see a black plastic box with a hinged lid. This is the power distribution box, also called the fuse box or battery junction box.

Step 2: Remove the lid by pressing the release tabs. On the inside of the lid, there is a diagram that shows the position and function of each fuse and relay. Look for a relay labeled “Fuel Pump” or “FP Relay.”

Step 3: According to multiple sources, the fuel pump relay is located at position 301 inside this box. It is a small, cube-shaped component, about 3/4 inch square, and is typically black or gray.

Step 4: The fuel pump relay is protected by a 20-amp fuse at position 10 in the same fuse box. Additionally, fuse 18 (15-amp) supplies power to the PCM, fuel injectors, and fuel pump relay. Before replacing the relay, check these fuses as well.

How to Test the Fuel Pump Relay

If you suspect the fuel pump relay is faulty, here are two simple ways to test it:

  1. Swap Test: Find an identical relay in the same fuse box. The horn relay (position 205) or the A/C clutch relay are often the same type. Swap the suspected fuel pump relay with one of these other relays. If the horn stops working but the engine starts, the original relay is bad.

  2. Listen for the Pump: Have an assistant turn the ignition key to the “On” position (not Start) while you listen near the fuel tank filler cap. You should hear a faint whirring sound for one to two seconds as the fuel pump primes. If you hear nothing, the relay or pump may be faulty.

Other Common Causes of Fuel Pump Failure

If the relay and fuses are good, but the pump still doesn’t run, check these components:

  • Inertia Switch: This safety switch is usually located in the passenger footwell or behind the kick panel. It cuts power to the fuel pump in the event of a collision. If it has been tripped, press the reset button on top.

  • Fuel Pump Driver Module (FPDM): Some 1999 F-150s use a separate fuel pump driver module, which can fail. The module is often mounted on the frame rail near the fuel tank.

  • Wiring Issues: Corroded or damaged wiring between the relay, fuse box, and fuel pump can prevent power from reaching the pump.

  • Clogged Fuel Filter: A severely clogged filter can cause the pump to work harder and eventually fail. Replace the fuel filter every 30,000 miles as preventive maintenance.

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay is a straightforward job that anyone can do in under five minutes.

  1. Locate the power distribution box under the hood.
  2. Identify the fuel pump relay at position 301.
  3. Grip the relay firmly and pull it straight out. No tools are needed.
  4. Insert the new relay, making sure it is fully seated. The relay is keyed, so it will only fit one way.
  5. Close the fuse box lid and test the vehicle.

A replacement relay for a 1999 Ford F-150 typically costs between $10 and $20 at auto parts stores. For a more complete solution, consider replacing the fuel pump relay module if your truck is equipped with a separate driver module.

Upgrade Your 1999 Ford F-150 with a High-Performance Fuel Pump

If you are replacing the fuel pump relay because the pump itself has failed, or if you want to ensure your F-150 has a dependable fuel delivery system for years to come, consider upgrading to a KEMSO Fuel Pump. KEMSO specializes in high-performance, OEM replacement fuel pumps that are built to exceed factory specifications. Every KEMSO pump is designed for direct fitment, making installation easy, and comes with a lifetime warranty for complete peace of mind.

Whether you need a fuel pump for daily driving, towing, or off-road use, KEMSO delivers reliability and performance you can count on. Visit their website to browse their full selection of fuel pumps and find the right fit for your 1999 Ford F-150: https://www.kemsoracing.com/

Final Thoughts

The 1999 Ford F-150 fuel pump relay is located in the under-hood power distribution box on the driver’s side, at relay position 301. It is a common point of failure that can prevent your truck from starting. Always check the fuses first, then test the relay using the swap method. If the relay is good, move on to the inertia switch, wiring, and the fuel pump itself. With this guide, you can diagnose and fix fuel delivery issues quickly and get your F-150 back on the road.

For a reliable, long-lasting replacement, choose KEMSO fuel pumps. Visit https://www.kemsoracing.com/ to find the perfect pump for your truck.


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