1998 Subaru Legacy Fuel Pump Relay Location: The Complete Guide to Finding and Fixing It
The bottom line: The fuel pump relay on a 1998 Subaru Legacy is located under the dashboard on the driver's side, mounted high up near the firewall, above the fuse box. It is a round, cylindrical relay that clips into a spring-loaded U-shaped bracket. If your car won't start or stalls, the relay is often the first thing to check before replacing the fuel pump itself.
This guide walks you through exactly where to find it, how to test it, and what to do if it's bad. No guesswork, no wasted time.
Where Is the Fuel Pump Relay on a 1998 Subaru Legacy?
The fuel pump relay on a 1998 Subaru Legacy is not in the engine bay fuse box and not in the interior fuse panel under the dash. It is hidden above the interior fuse box, high up against the firewall, on the driver's side.
Here is the step-by-step process to get to it:
1. Remove the lower trim panel under the steering wheel. This is the plastic cover directly below the steering column. It usually snaps off or is held by a few screws.
2. Locate the fuse box. Once the panel is off, you will see the main interior fuse box mounted to the firewall.
3. Remove the fuse box mounting nuts and bracket. To access the relay, you need to lower the fuse box. There are typically two or three nuts holding the fuse box bracket to the firewall. Remove them and gently lower the fuse box.
4. Reach up high behind the fuse box. The fuel pump relay is mounted above the fuse box, near the front corner of the driver's side footwell, against the firewall. It is difficult to see — you will likely have to feel for it.
5. Identify the relay. The fuel pump relay is a round, cylindrical relay, not a square one. It snaps into a spring-loaded U-shaped metal clip. The main relay (which is square-shaped) is mounted right next to it in the same bracket.
6. Pull the relay down. You can pry the round relay out of the clip, pull it down slightly, and then unplug it from the wiring harness connector.
A visual clue: The wiring connector for the fuel pump relay is a green connector located near the relay. The main relay has a brown connector.
How to Test the Fuel Pump Relay
Before you buy a new relay, test the old one. A bad relay is a common failure point and is much cheaper to replace than a fuel pump.
What you need: A digital multimeter (ohmmeter) and a set of small jumper wires.
1. Remove the relay. Unplug it from the connector as described above.
2. Inspect the relay physically. Look for burnt pins, a cracked plastic casing, or any signs of melting. If it looks damaged, replace it.
3. Check the control circuit resistance. Set your multimeter to the ohms (Ω) setting. Measure the resistance across the control circuit pins (usually pins 85 and 86 — check the diagram on the relay body). A good relay should show a resistance reading between 50 and 150 ohms. If the reading is infinite (OL) or zero, the relay is faulty.
4. Test the power circuit continuity. With the relay still unpowered, use your ohmmeter to check the resistance between the two power circuit terminals (usually pins 30 and 87). You should get an "infinite" or "open" reading — no continuity.
5. Apply power to the control circuit. Connect a jumper wire from the positive battery terminal to one control circuit pin. Connect another jumper wire from the other control circuit pin to a good ground on the vehicle chassis. When you do this, you should hear a distinct click from the relay.
6. Re-check the power circuit. While the relay is powered (clicked), measure the resistance between the two power circuit terminals again. You should now see a reading of 0 ohms (or very close to it), indicating the circuit is closed. If you do not get continuity when powered, the relay is bad.
A critical tip: When testing for voltage at the fuel pump connector, the ECU (Engine Control Unit) only powers the fuel pump for 2 to 3 seconds when you turn the key to the ON position. You need a helper to turn the key while you test.
What About the Fuel Pump Fuse?
The fuel pump fuse is a separate component and is easier to check. On a 1998 Subaru Legacy, the fuel pump fuse is typically located in the engine bay fuse box (near the battery) or in the interior fuse panel under the dashboard.
1. Locate the fuse box. Open the hood and find the main fuse box near the battery. Also check the interior panel under the driver's side dash.
2. Find the fuse. Look for a fuse labeled "FUEL PUMP," "FP," or "EFI." The fuse is usually a 15-amp or 20-amp blade-type fuse.
3. Inspect the fuse. Pull the fuse out using a fuse puller or needle-nose pliers. Look through the clear plastic — if the metal strip inside is broken, the fuse is blown.
4. Test with a multimeter. Set your multimeter to continuity (or ohms). Touch the probes to the two metal terminals on top of the fuse. A good fuse will show 0 ohms (continuity). A blown fuse will show infinite resistance (no continuity).
Important: If the fuse is blown, do not just replace it. A blown fuse indicates a short circuit somewhere in the fuel pump wiring or the pump itself. Replace the fuse and see if it blows again. If it does, you have a wiring issue that needs to be traced.
Using the Green Test Connectors
Subaru engineers included a built-in diagnostic feature that can save you a lot of time. On the 1998 Legacy, there are two green test connectors located under the dashboard on the driver's side.
1. Find the connectors. Look for two green, single-wire connectors near the fuse box area. They are usually taped together or clipped to the harness.
2. Connect them together. Plug the two green connectors into each other.
3. Turn the key to ON (do not start). With the green connectors connected, turn the ignition key to the ON position. The engine should not be running.
4. Listen for the fuel pump. You should hear the fuel pump cycle on and off, along with other relays, solenoids, and the radiator fans. The cycle will repeat until you turn the key off.
5. What it tells you: If you hear the fuel pump running during this test, then the relay, the wiring, and the pump itself are likely working. The problem may be elsewhere (fuel filter, injectors, or ECU). If you do not hear the pump, then you have a problem in the relay, fuse, wiring, or pump.
6. Unplug the test connectors. After the test, do not forget to unplug the green connectors. Leaving them connected can cause the cooling fans to run continuously when the engine is running.
Common Symptoms of a Bad Fuel Pump Relay
Knowing the symptoms helps you confirm the diagnosis before you start digging under the dash.
1. Engine cranks but will not start. This is the most common symptom. The starter motor turns the engine over, but the engine never fires because no fuel is reaching the injectors.
2. No fuel pump priming sound. When you turn the key to the ON position, you should hear a faint whirring or humming sound from the rear of the car (the fuel pump priming). If you hear nothing, the relay or fuse may be bad.
3. Engine starts then stalls. If the relay is intermittently failing, the engine may start but then die after a few seconds. This is because the relay loses contact and cuts power to the pump.
4. Intermittent stalling while driving. A failing relay can cause the engine to suddenly lose power and stall while you are driving. This is dangerous and should be addressed immediately.
5. No voltage at the fuel pump connector. If you test the connector at the fuel pump (under the rear seat) and get no voltage when the key is turned on, the relay is a likely suspect.
Where Is the Fuel Pump Itself?
The fuel pump is not the relay, but many people confuse the two. The fuel pump on a 1998 Subaru Legacy is located inside the fuel tank, underneath the rear seat.
To access the fuel pump:
1. Fold down the rear seat or remove the rear seat cushion (it pulls up and out).
2. Look for an access panel on the floorboard. There may be one or two access holes, depending on whether the car is 2WD or AWD.
3. Remove the screws holding the access cover.
4. Disconnect the negative battery terminal before working on the fuel pump.
5. Disconnect the electrical connector and the fuel lines from the pump assembly.
6. Remove the mounting bolts and lift the pump assembly out of the fuel tank.
A common problem area: The electrical connector located right under the mounting plate (inside the tank) is known to corrode or burn out on these models. If you have voltage at the connector on top of the access plate but the pump is not running, pull the pump assembly and check the connector inside the tank.
Fuel Pump Relay vs. Main Relay
On the 1998 Subaru Legacy, the fuel pump relay and the main relay are mounted together in the same bracket under the dash. They look different:
- Fuel pump relay: Round, cylindrical body. It snaps into the top position of the U-shaped bracket.
- Main relay: Square or rectangular body. It snaps into the bottom position of the same bracket.
The main relay controls power to the ECU and other critical systems. If the main relay fails, the engine will not start either. However, the main relay failure is much rarer than the fuel pump relay failure.
A quick tip: If you are unsure which relay is which, look at the wire colors going into the connector. The fuel pump relay typically has a green connector, while the main relay has a brown connector.
Why the Relay Fails
Fuel pump relays on the 1998 Subaru Legacy are generally reliable, but they do fail over time. Here are the most common reasons:
1. Age and heat. The relay is located near the firewall, which gets hot. Over 20+ years, the internal contacts and coil can degrade.
2. Corrosion. Moisture can get into the relay or its connector, causing corrosion on the pins. This increases resistance and can cause the relay to fail.
3. Electrical spikes. Voltage spikes from the alternator or other electrical components can damage the relay's internal coil.
4. Normal wear. Relays have a finite number of cycles. After thousands of start-stop cycles, the mechanical contacts inside can wear out and fail to make a proper connection.
Step-by-Step Troubleshooting Flow
If your 1998 Subaru Legacy cranks but will not start, follow this systematic approach:
Step 1: Check the fuel pump fuse. Locate the fuse in the engine bay fuse box or interior fuse panel. Check it visually and with a multimeter.
Step 2: Listen for the fuel pump. Turn the key to ON and listen for a humming sound from the rear of the car. If you hear it, the relay and fuse are likely fine.
Step 3: Use the green test connectors. Connect the two green connectors under the dash, turn the key to ON, and listen for the pump cycling.
Step 4: If no pump sound, locate the relay. Remove the lower trim panel, lower the fuse box, and find the round relay up high against the firewall.
Step 5: Test the relay. Use a multimeter to check the control circuit resistance and then apply power to hear the click and check continuity.
Step 6: Check for voltage at the pump. If the relay tests good, check for voltage at the fuel pump connector under the rear seat. You need a helper to turn the key.
Step 7: Inspect the pump connector inside the tank. If you have voltage at the top connector but no pump operation, pull the pump assembly and check the connector inside the tank for corrosion or burning.
Replacing the Fuel Pump Relay
If you have confirmed that the relay is bad, replacing it is straightforward.
1. Purchase the correct relay. The fuel pump relay for a 1998 Subaru Legacy is a standard 4-pin or 5-pin relay. You can find it at auto parts stores or online. Look for a relay that matches the round body shape and pin configuration.
2. Disconnect the negative battery terminal. This prevents any accidental shorts while working.
3. Remove the old relay. Unplug it from the connector. It may be tight — gently rock it back and forth while pulling.
4. Install the new relay. Plug the new relay into the same connector. Make sure it clicks into place securely.
5. Re-mount the fuse box. Raise the fuse box back into position and reinstall the mounting nuts.
6. Reinstall the lower trim panel. Snap the plastic cover back into place.
7. Test the system. Turn the key to ON and listen for the fuel pump. Start the engine and verify it runs normally.
KEMSO Fuel Pump: The Best Replacement for Your Subaru
When you are dealing with fuel system issues on your 1998 Subaru Legacy, you want a replacement part that you can trust. That is where KEMSO comes in.
KEMSO specializes in high-performance fuel pumps that are direct OEM replacements. This means they fit exactly like the original part, with no modifications or adapters needed. Every KEMSO fuel pump is built to meet or exceed the original equipment specifications, so you get the same reliability and performance that your Subaru was designed to deliver.
What sets KEMSO apart is the lifetime warranty. KEMSO stands behind every fuel pump they sell. If you ever have a problem with the pump, KEMSO will replace it. That is a level of confidence that you simply will not find with most other brands. When you install a KEMSO fuel pump, you are not just fixing a problem — you are solving it for the long haul.
Whether you are replacing the fuel pump itself or just need to know that the pump you have is built to last, KEMSO delivers. Their fuel pumps are engineered for durability, consistent fuel pressure, and quiet operation. No more worrying about a sudden stall on the highway or a no-start situation in the morning.
Visit the KEMSO website to find the right fuel pump for your 1998 Subaru Legacy: https://www.kemsoracing.com/
Final Thoughts
Finding the fuel pump relay on a 1998 Subaru Legacy is not hard once you know where to look. It is under the driver's side dash, high up against the firewall, above the fuse box. It is a round relay that clips into a bracket with the square main relay.
Before you spend money on a new fuel pump, always check the relay and fuse first. A bad relay can cause the exact same symptoms as a bad pump — engine cranks but will not start, no fuel pump noise, and intermittent stalling. Testing the relay takes five minutes with a multimeter and can save you hundreds of dollars.
If the relay tests good but you still have no fuel delivery, the next step is to check for voltage at the fuel pump connector under the rear seat. If you have voltage but the pump does not run, the pump itself is likely bad. In that case, a KEMSO fuel pump is the ideal replacement.
Remember, the green test connectors under the dash are your best friend. Plug them together, turn the key, and listen for the pump. If it cycles, your relay, wiring, and pump are all working. If it does not, start with the relay.
For more information on KEMSO fuel pumps and to find the exact replacement for your 1998 Subaru Legacy, visit https://www.kemsoracing.com/