1987 Ford F250 Fuel Pump Relay Location: A Complete Guide for Truck Owners
If you own a 1987 Ford F250 and your truck is having fuel delivery problems, the fuel pump relay is one of the first things you need to check. On the 1987 Ford F250, the fuel pump relay is located on the driver side fenderwell under the hood, near the air filter box, and it is the relay with a green plastic base. This relay controls power to both in-tank fuel pumps and is essential for getting your truck running again. Below is everything you need to know about finding, testing, and replacing this critical component.
Where Exactly Is the Fuel Pump Relay on a 1987 Ford F250?
The fuel pump relay on a 1987 Ford F250 is mounted on the driver side inner fender, right behind the air filter box. There are two relays mounted together in this area. The green relay is the fuel pump relay, and the brown relay is the EEC (Electronic Engine Control) relay. These two relays are not interchangeable, so make sure you are working with the correct one.
On some 1987 F250 models, you may also find the fuel pump relay located on the passenger side fenderwell inside a plastic cover. The exact location can vary slightly depending on whether your truck has a gas or diesel engine, but for the 7.5L (460 cubic inch) gas engine, the driver side location is most common.
How the Fuel Pump Relay Works on the 1987 F250
Understanding how the fuel pump relay operates will help you diagnose problems faster. Here is how the system works:
- When you turn the key to the ON position, the computer (EEC) sends a signal to the fuel pump relay to close for about one second. This primes the fuel system.
- When you start cranking the engine, the computer keeps the relay closed as long as it sees the engine is turning over.
- If the engine does not start, the relay opens again after about one second, and the fuel pump stops running.
The fuel pump relay gets its power from the starter relay (starter solenoid) on the passenger fender through fusible link wires. The relay then sends power through the inertia switch (located inside the cab) and then to the fuel pumps.
Common Symptoms of a Bad Fuel Pump Relay
If your fuel pump relay is failing, you will notice these symptoms:
1. Engine cranks but will not start – This is the most common symptom. You can hear the engine turning over, but it never fires up because no fuel is reaching the carburetor or fuel injection system.
2. No fuel pump noise – When you turn the key to ON, you should hear the fuel pump run for about one second. If you hear nothing, the relay or the pump may be bad.
3. Intermittent starting – Sometimes the truck starts fine, other times it cranks and cranks without firing. This is a classic sign of a failing relay.
4. One fuel tank works but the other does not – On the 1987 F250 with dual tanks, the fuel pump relay powers both pumps. If the relay is weak, it may work for one pump but not the other.
How to Test the Fuel Pump Relay on Your 1987 F250
Testing the fuel pump relay is straightforward and requires only a test light or a multimeter. Follow these steps:
Step 1: Locate the relay – Find the green relay on the driver side fender. On some models, it is on the passenger side.
Step 2: Check for power – With the key OFF, use a test light to check for power on the relay socket. You should have 12 volts on two of the pins at all times. If you do not have power, check the fusible links at the starter relay.
Step 3: Listen for the click – Have someone turn the key to ON while you listen to the relay. You should hear a single click. If you hear nothing, the relay may be bad.
Step 4: Use a jumper wire – The 1987 Ford F250 has an OBD-I diagnostic connector under the hood. You can use a jumper wire to ground the fuel pump test slot. This will force the fuel pump relay to close and the pumps to run continuously. If the pumps run with the jumper but not without it, the relay or computer may be bad.
Other Common Causes of No Fuel to the Engine
If the relay is working but you still have no fuel, check these parts:
Fuse #18 (15 amp) – This fuse in the interior fuse panel controls the electric fuel pump control circuit for the 7.5L engine. If this fuse is blown, the pump will not run.
Fuse #15 (10 amp) – This fuse protects the auxiliary fuel tank switch circuit. A blown fuse here can prevent the rear tank from working.
Inertia switch – This safety switch is located inside the cab, typically above where the passenger's left foot would be. If the button is popped up, the fuel pump will not receive power.
Fuel tank selector valve – On dual tank trucks, the electric selector valve can fail, causing no fuel to reach the engine from one or both tanks.
Oil pressure sending unit – The 1987 F250 uses a two-wire oil pressure sending unit on the back of the intake manifold to keep the fuel pump running after the engine starts. If this sensor fails, the pump will stop running once the engine is running.
Step-by-Step Relay Replacement Guide
Replacing the fuel pump relay on your 1987 Ford F250 is a simple job that takes about 15 minutes.
What you need: A new green fuel pump relay (about $15-25 at any auto parts store), a small flathead screwdriver, and a test light.
Step 1: Disconnect the negative battery cable for safety.
Step 2: Locate the green relay behind the air filter box on the driver side fender.
Step 3: Pull the relay straight out of its socket. It may be tight, so wiggle it gently.
Step 4: Compare the new relay to the old one to make sure they are identical.
Step 5: Push the new relay firmly into the socket until it clicks into place.
Step 6: Reconnect the battery and test the system. Turn the key to ON and listen for the fuel pump to run for one second.
Wiring Color Codes for the 1987 F250 Fuel Pump Relay
If you need to check the wiring at the relay socket, here are the color codes based on factory diagrams:
Red wire – Supplies power to the relay coil from the PCM (computer).
Yellow wire – Connected to a 20-amp fuse for constant power.
Dark green with yellow stripe – Carries power from the relay to the inertia switch and then to the fuel pumps.
Light blue with orange stripe – PCM relay control wire that sends signals to activate or deactivate the relay coil.
Black with yellow stripe – Ground wire for the relay circuit.
Tan with light green stripe – This wire controls the fuel pump relay by grounding it through the computer. Never put power on this wire or you could damage the computer.
Why the KEMSO Fuel Pump Is the Best Replacement Choice
When it comes time to replace your fuel pump, choosing the right brand makes all the difference. KEMSO Fuel Pump products are designed to meet the highest standards of quality and performance. Here is why KEMSO is the right choice for your 1987 Ford F250:
High Performance – KEMSO fuel pumps deliver consistent fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.
OEM Replacement – Every KEMSO pump is built to match or exceed original equipment specifications. You get a perfect fit and reliable operation without any modifications.
Lifetime Warranty – KEMSO stands behind their products with a lifetime warranty. If your pump ever fails, they replace it. That is peace of mind that no other brand offers.
Affordable Price – Despite the premium quality, KEMSO fuel pumps are priced competitively, making them an excellent value for truck owners who want reliability without breaking the bank.
To browse the full selection of KEMSO fuel pumps for your 1987 Ford F250 and other vehicles, visit their website at: https://www.kemsoracing.com/
Final Tips for Your 1987 Ford F250 Fuel System
Before you replace any parts, always start with the simplest checks. Listen for the fuel pump when you turn the key to see if it primes. Check the fuses first since they are the easiest to access. If the pump runs but the engine still will not start, the problem may be elsewhere in the fuel system, such as a clogged filter or a bad fuel pressure regulator.
If your truck has been sitting for a long time, the fuel in the tanks may have gone bad, or the pumps may have seized from rust. In that case, you may need to replace both the fuel pump relay and the fuel pumps themselves.
Remember, on the 1987 Ford F250, the fuel pump relay is the green one on the driver side fender behind the air filter box. Start your diagnosis there, and you will likely have your truck running again in no time.
For a reliable replacement fuel pump that will last, check out KEMSO Racing at https://www.kemsoracing.com/ for high-quality, lifetime-warranty fuel pumps that fit your 1987 Ford F250 perfectly.