1991 Honda Accord Fuel Pump Relay Location: Your Ultimate Guide

Locating the fuel pump relay in your 1991 Honda Accord is straightforward: It is found inside the vehicle's interior fuse box panel, mounted on the lower dashboard near the driver's left knee, just below and slightly to the left of the steering column. Identifying the correct relay requires knowing its specific position within the panel or recognizing it by its distinct color and pin configuration.

For any 1991 Honda Accord owner experiencing engine starting problemsโ€”such as the engine cranking but not firing upโ€”a failing fuel pump relay is a prime suspect. Understanding its exact location and how to access it is crucial for diagnosis and replacement. This guide provides the definitive, step-by-step instructions you need.

Detailed Access Procedure for the Interior Fuse Box

  1. Prepare the Vehicle: Park your Accord on a level surface. Engage the parking brake firmly. Turn the ignition switch completely to the "OFF" position. Remove the key from the ignition cylinder.
  2. Lower the Steering Column (Optional but Helpful): Many drivers find access easier if they release the steering column tilt lever and lower the steering wheel to its lowest position.
  3. Position Yourself: Sit in the driver's seat. Look down towards your left leg, near where it meets the area underneath the dashboard.
  4. Locate the Fuse Box Cover: You will see a rectangular or slightly trapezoidal plastic panel. This is the cover for the interior fuse and relay panel.
  5. Remove the Cover: The cover is held in place by simple plastic clips or tabs. Using your fingers, gently pry the bottom edge of the cover outward. It should release easily without requiring excessive force. Pull the cover straight towards you and set it aside safely.
  6. Identify the Fuel Pump Relay: With the cover removed, you now see the array of fuses and several cube-shaped relays. Relays are larger than fuses. Look specifically at the relays positioned on the leftmost column of the fuse box panel (closest to the driver's door).
    • The Fuel Pump Relay (Main Relay) is typically the topmost relay in this left column. It is the relay closest to the upper edge of the fuse box assembly, sitting above other relays like the Cooling Fan Relay.
    • Visual Identification: The 1991 Accord's fuel pump relay is often (but not always) green in color. Crucially, it is a square, cube-shaped relay with four prongs or terminals on its bottom side. A label inside the fuse box cover should also clearly identify "FUEL PUMP" or "MAIN" (sometimes the fuel pump relay is part of the combined "Main Relay" unit controlling both fuel pump and engine computer power in earlier Honda designs). If the cover label is missing or faded, its position (top-left) and 4-pin configuration are the key identifiers.

Why Knowing the Fuel Pump Relay Location Matters

The fuel pump relay acts as a crucial electrical switch controlled by your Accord's engine computer. Its primary job is to supply high-current electrical power to the fuel pump located inside the fuel tank. When you turn the ignition key to the "ON" position (before cranking), the relay should click on, sending power to the fuel pump for a few seconds to pressurize the fuel system. During cranking and engine operation, it remains powered on. A faulty relay will cut power to the fuel pump, preventing the engine from starting or causing it to stall unexpectedly, mimicking symptoms of a failed fuel pump or ignition problem.

Symptoms Indicating a Potential Fuel Pump Relay Problem

  • Engine Cranks But Won't Start: The most common symptom. You hear the starter motor turning the engine over normally, but the engine does not fire up or run.
  • Engine Starts Intermittently: The car might start fine sometimes, but fail to start on other occasions, with no obvious pattern.
  • Engine Stalls While Driving: The engine suddenly cuts out during operation as if the ignition was turned off.
  • No Fuel Pump Prime Sound: When you turn the ignition key to "ON" (without cranking), you should normally hear a faint humming or buzzing sound from the rear of the car (near the fuel tank) for about 2 seconds. A lack of this sound strongly points to a relay, fuse, wiring, or pump issue.
  • Clicking Sound From Relay Area: Sometimes a failing relay may emit a rapid clicking sound from the dashboard fuse panel when the ignition is turned on, indicating it's trying but failing to engage properly.

Testing the 1991 Honda Accord Fuel Pump Relay

Once you've located the relay, testing it is a logical next step before replacement:

  1. Swap Test (Simplest Method): Since identical relays often control different circuits (like the Cooling Fan or AC Compressor), find another relay in the fuse box with the exact same appearance and number of pins. Carefully swap the suspect fuel pump relay with this known good relay. If the engine now starts and runs properly, your original fuel pump relay is faulty. Replace it.
  2. Listen and Feel Test: Turn the ignition key to the "ON" position. Have a helper do this while you place your fingers gently on the fuel pump relay. You should feel and hear a distinct "click" within 1-2 seconds of turning the key to "ON". The click signifies the relay is engaging. If you don't feel or hear a click, it suggests the relay isn't activating. Repeat this several times to confirm. Note: A click doesn't guarantee the internal contacts are good, but no click strongly suggests a problem with the relay or its control signal.
  3. Electrical Testing (Multimeter Required): This is the most definitive test but requires a digital multimeter.
    • Identify Terminals: The relay bottom has four prongs/terminals. Two terminals (usually 85 & 86) are for the low-current control coil that activates the relay. The other two (usually 87 & 30) are the high-current switched contacts that power the fuel pump.
    • Test Coil Resistance: Set the multimeter to Ohms (โ„ฆ). Place probes on terminals 85 and 86. A good relay coil typically shows resistance between 50-150 Ohms. Infinite resistance means an open coil.
    • Test Contact Resistance: Place probes on terminals 87 and 30. Should show infinite resistance (OL or similar) when the relay is deactivated. Apply 12 volts to terminals 85 (+) and 86 (-) to activate the relay. The contacts (87-30) should now show near 0 Ohms (continuity). Infinite resistance when activated means bad contacts.
    • Test Voltage: With the relay plugged into its socket and ignition turned to "ON," carefully back-probe the wires at the socket terminals using multimeter probes. Confirm you have 12V+ on the high-current supply terminal (often pin 30 - constantly live from battery) and on the control coil terminal getting switched power from the ECU (usually pin 86) when the key is "ON". Ground should be present on the other coil terminal (pin 85). The output terminal (pin 87) should go to 12V+ when the relay clicks on.

Replacing the Fuel Pump Relay in Your 1991 Accord

If testing confirms a failed relay, replacement is simple:

  1. Purchase the Correct Relay: Obtain a replacement relay. Honda part numbers for the Main/Fuel Pump relay for this model year are commonly 38400-SS0-A01 (Mitsuba), 39400-SR2-003, or equivalents. Ensure it is specifically listed for the 1991 Accord fuel system and has four pins. A standard Bosch-style 30 Amp 4-pin relay will also work correctly as a replacement.
  2. Access the Relay: Follow steps 1-5 above to remove the interior fuse box cover.
  3. Remove the Old Relay: Locate the fuel pump relay in the top-left position. Grip it firmly and pull it straight down and out of its socket. Do not twist or rock it excessively.
  4. Install the New Relay: Orient the new relay so its pins align with the socket holes. Look at the base of the relay; the pins may be offset or of differing sizes/shapes to ensure proper orientation. Match these to the socket. Push the relay straight down into the socket with firm, even pressure until it seats fully.
  5. Reinstall the Cover: Position the fuse box cover back onto the panel and press firmly until all clips or tabs snap securely into place.
  6. Test Operation: Turn the ignition key to "ON" and listen for the fuel pump prime sound. Then, attempt to start the engine.

Important Considerations and Safety Tips

  • Battery Disconnection: While not strictly necessary just for relay removal/replacement, disconnecting the negative battery terminal provides extra safety against accidental short circuits. Always disconnect the negative terminal first and reconnect it last.
  • Fuse Check: The fuel pump circuit is protected by a fuse located within the same interior fuse box. Identify the fuse labeled "FUEL PUMP" (often a 15 Amp fuse) and check it visually for a broken filament. Replace it if blown.
  • Wiring: While the relay is the most common failure point, inspect the wiring connector at the relay socket for any signs of burning, melting, corrosion, or damaged pins. Problems here could mimic relay failure.
  • Quality Parts: Use relays from reputable brands. Cheap, generic relays are prone to early failure and can leave you stranded.
  • Persistent Problems: If replacing the relay doesn't solve the no-start issue, further diagnosis of the fuel pump itself (access is via an access panel under the rear seat cushion), fuel pump wiring, ignition system, or ECU may be necessary.

Finding and addressing the fuel pump relay in your 1991 Honda Accord is a manageable task for most owners. By knowing exactly where to look (lower dash, driver's side fuse box, top-left relay slot), understanding how to test it, and replacing it with confidence, you can quickly resolve a common cause of no-start issues and keep your reliable Accord running smoothly.

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