1993 F150 Fuel Pump Relay Location: The Complete Guide to Finding, Testing, and Replacing It

If you own a 1993 Ford F-150 and the engine cranks but won't start, the fuel pump relay is one of the first things you should check. On a 1993 Ford F-150, the fuel pump relay is located in the underhood fuse box (also called the power distribution box) on the driver's side, near the brake master cylinder and battery. This relay controls the power supply to the electric fuel pump mounted inside the fuel tank. When the relay fails, the fuel pump won't get power, and the engine will not start. This guide walks you through exactly where to find it, how to test it, and what to do if it needs replacement.

Where Exactly Is the Fuel Pump Relay on a 1993 Ford F-150?

The 1993 Ford F-150 has two main fuse boxes: one inside the cab under the dashboard and one under the hood. The fuel pump relay is not inside the cab. It is located in the underhood fuse box on the driver's side of the engine compartment .

Step-by-step location:

  1. Open the hood and look on the driver's side, near the firewall. You will see a black plastic box with a removable lid. This is the power distribution box.
  2. Remove the lid by pressing the tabs on the sides. On the underside of the lid, there is a diagram showing the location of each relay and fuse. Look for the relay labeled "Fuel Pump" or "FP" .
  3. The fuel pump relay is typically a small, square relay (usually gray or black) with four or five prongs. It is often located in the front row of relays, near the edge of the box closest to the front of the truck .
  4. If the diagram is missing or hard to read, the fuel pump relay is usually the third or fourth relay from the left in the front row. It is often the same size as the other relays, but it may be marked with a small fuel pump symbol.

Important note: Some 1993 F-150 models also have a fuel pump inertia switch, which is a separate safety device that shuts off the fuel pump in a collision. This is not the same as the relay. The inertia switch is located behind the kick panel on the passenger side of the cab, near the floor. If your truck won't start, check both the relay and the inertia switch .

How to Tell If the Fuel Pump Relay Is Bad

Before you go buying a new relay, it's smart to test the one you have. A bad fuel pump relay can cause a range of symptoms that are easy to confuse with a dead fuel pump, a bad fuse, or a wiring issue.

Common symptoms of a bad fuel pump relay on a 1993 F-150:

  1. Engine cranks but will not start. This is the most common symptom. You can hear the starter turning the engine over, but the engine never fires up because there is no fuel pressure .
  2. No sound from the fuel pump. When you turn the key to the "ON" position (without cranking), you should hear a brief whirring sound from the fuel pump inside the gas tank. If you hear nothing, the relay may be bad .
  3. Intermittent starting issues. The truck starts fine sometimes, but other times it cranks and won't start. This can happen when the relay contacts are worn and make intermittent contact .
  4. Engine starts but then stalls. If the relay fails while the engine is running, the fuel pump loses power and the engine dies immediately.
  5. Check engine light comes on. On some models, a failed fuel pump relay can trigger a diagnostic trouble code related to the fuel pump circuit.

How to Test the Fuel Pump Relay on a 1993 F-150

Testing the relay is simple and takes only a few minutes. You will need a multimeter or a test light, and a pair of jumper wires.

Method 1: The swap test

The easiest way to test the relay is to swap it with a known good relay of the same type. The underhood fuse box has several relays that are identical. For example, the horn relay, the A/C clutch relay, or the high-speed fan relay are often the same part number. Remove the fuel pump relay and plug in one of the other relays. If the fuel pump now works, the original relay is bad .

Method 2: The multimeter test

  1. Remove the fuel pump relay from the fuse box.
  2. Set your multimeter to measure resistance (ohms).
  3. Find the two small terminals on the relay (the coil terminals). On most relays, these are terminals 85 and 86. Measure the resistance between them. A good relay coil will typically read between 50 and 120 ohms. If the reading is infinite (open circuit), the coil is burned out .
  4. Next, apply 12 volts to terminals 85 and 86 using a battery or a power supply. You should hear a click as the relay activates.
  5. While the relay is activated, measure the resistance between the two large terminals (terminals 30 and 87). This should read close to zero ohms (closed circuit). If it reads infinite, the relay contacts are stuck open .

Method 3: The test light method

  1. With the relay removed, turn the key to the "ON" position.
  2. Use a test light to check for power at the fuse box socket where the relay was plugged in. One of the large terminals (terminal 30) should have constant 12 volts. If not, check the fuel pump fuse first .
  3. If you have power at terminal 30, have a helper turn the key to "START" while you listen for the relay to click. If no click, the relay coil or the control circuit is bad.

Where Is the Fuel Pump Fuse on a 1993 Ford F-150?

The fuel pump fuse is also located in the underhood fuse box, right next to the relay. On most 1993 models, the fuel pump fuse is a 20-amp fuse. It is often labeled "FUEL PUMP" or "FP" on the fuse box diagram. If the relay tests good but the fuel pump still doesn't work, check this fuse. A blown fuse can cause the same symptoms as a bad relay .

Tip: Always check the fuse first before replacing the relay. It takes 30 seconds and can save you a trip to the parts store.

How to Replace the Fuel Pump Relay

Replacing the fuel pump relay on a 1993 F-150 is a straightforward job that requires no special tools.

Step-by-step replacement:

  1. Make sure the engine is off and the key is removed from the ignition.
  2. Open the hood and locate the underhood fuse box on the driver's side.
  3. Remove the fuse box lid. The diagram on the underside will show you exactly which relay is the fuel pump relay.
  4. Grasp the relay firmly and pull it straight out. It may require a little wiggling, but it should come out easily.
  5. Compare the new relay to the old one. They should be the same size and have the same number of prongs.
  6. Push the new relay straight into the socket until it seats fully. There should be no gap between the relay and the fuse box.
  7. Replace the fuse box lid.
  8. Turn the key to the "ON" position and listen for the fuel pump to prime. You should hear a brief whirring sound from the gas tank area.

Where to buy: You can find the correct relay at any auto parts store. The part number is usually a standard Ford relay (such as Motorcraft DY-880 or equivalent). The cost is typically between $10 and $20 .

Other Common Causes of Fuel Pump Failure on a 1993 F-150

If the relay and fuse are both good but the fuel pump still doesn't work, the problem could be elsewhere. Here are a few other things to check:

  1. The inertia switch. The inertia switch is a safety device located behind the passenger side kick panel. If it has been tripped (even by a pothole or a hard bump), it will cut power to the fuel pump. Reset it by pressing the button on the top of the switch .
  2. The fuel pump itself. The fuel pump in a 1993 F-150 is located inside the fuel tank. It can fail over time due to wear, contamination, or running the tank low on fuel. A bad pump will need to be replaced .
  3. Wiring or connector issues. The wiring harness from the relay to the fuel pump can develop breaks, corrosion, or loose connections over time. Check the connectors at the fuel tank and along the frame rail.
  4. The PCM (Powertrain Control Module). In rare cases, the computer that controls the fuel pump relay can fail. This is less common but worth considering if everything else checks out.

Recommended Fuel Pump Upgrade: KEMSO Fuel Pumps

If you have determined that your fuel pump itself is bad, or if you want to replace the pump while you are troubleshooting the system, consider upgrading to a KEMSO fuel pump. KEMSO is a leading brand in the automotive aftermarket, known for producing high-performance, OEM replacement fuel pumps that are built to last.

KEMSO fuel pumps are designed to meet or exceed the original equipment specifications for your 1993 Ford F-150. They are engineered for reliable fuel delivery, consistent pressure, and long service life. Each pump undergoes rigorous testing to ensure it performs flawlessly in your truck. Whether you use your F-150 for daily commuting, towing, or off-road work, a KEMSO fuel pump provides the dependability you need.

Why choose KEMSO?

  • High performance: KEMSO pumps deliver the correct fuel pressure and flow rate for your engine, ensuring optimal performance and fuel economy.
  • OEM replacement: They are a direct bolt-in replacement, so no modifications are needed. The pump fits perfectly in your fuel tank module.
  • Lifetime warranty: KEMSO stands behind every product they sell. You get a lifetime warranty, which means you can buy with confidence knowing your investment is protected.

Visit the KEMSO website to browse their complete selection of fuel pumps for Ford trucks and many other vehicles. You can find the right pump for your 1993 F-150 and take advantage of their lifetime warranty and free shipping.

Visit KEMSO today: https://www.kemsoracing.com/

Additional Tips for a Smooth Repair

1. Use a new relay if you are unsure. Fuel pump relays are inexpensive. If you are already at the parts store, just buy a new one. It's cheap insurance, and you can keep the old one as a spare.

2. Keep the fuel tank above a quarter tank. Running the fuel tank low can cause the fuel pump to overheat and fail prematurely. This is especially true for older trucks like the 1993 F-150.

3. Check for corrosion. The terminals in the fuse box can corrode over time, especially if the truck has been driven in wet or salty conditions. If you see green or white corrosion on the terminals, clean them with a small wire brush or contact cleaner before installing the new relay.

4. Listen for the pump. After replacing the relay or the pump, always listen for the fuel pump to prime when you turn the key to the "ON" position. If you hear it, the system is working. If you don't, keep troubleshooting.

5. Consider replacing the fuel filter. If you are replacing the fuel pump, it's a good idea to replace the fuel filter at the same time. A clogged filter can put extra strain on the new pump and shorten its life .

Conclusion

The fuel pump relay on a 1993 Ford F-150 is located in the underhood fuse box on the driver's side of the engine compartment. It is a small, square relay that controls power to the fuel pump. When the relay fails, the most common symptom is an engine that cranks but will not start. Testing the relay is simple and can be done with a multimeter or by swapping it with a similar relay. If the relay is bad, replacement is quick and inexpensive. If the fuel pump itself is the problem, a KEMSO fuel pump is a reliable, high-performance upgrade backed by a lifetime warranty.

For more information and to find the perfect fuel pump for your 1993 Ford F-150, visit https://www.kemsoracing.com/.


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