2004 Honda Accord Fuel Pump Relay Location: Find & Fix It Fast

The fuel pump relay on your 2004 Honda Accord is located inside the under-hood fuse and relay box, specifically in position #2 (often labeled "Fuel Pump"). This black plastic box is typically mounted near the battery on the driver's side of the engine compartment.

Troubleshooting a car that cranks but won't start often points towards fuel delivery issues. When it's a 2004 Honda Accord, one of the most common culprits checked by mechanics and savvy DIYers alike is the fuel pump relay. Understanding where this crucial relay is located and how identify and resolve problems with it can save you significant time, money, and frustration compared to immediately suspecting a failed fuel pump. This guide provides the exact steps to locate, access, test, and replace the fuel pump relay on your specific model year Accord.

Finding the Under-Hood Fuse and Relay Box

The first step is identifying the main power distribution center in your engine bay, often referred to as the under-hood fuse/relay box or fuse panel. On the 2004 Honda Accord:

  1. Open the hood.
  2. Locate the vehicle's battery on the driver's side of the engine compartment.
  3. Directly adjacent to the battery, mounted to the body wall separating the engine compartment from the passenger cabin, you'll find a rectangular or trapezoidal black plastic box. It is usually held down by clips or a single bolt near the front edge.
  4. This box houses critical fuses and relays, including the main relay and the fuel pump relay.

Understanding Layout and Position #2

Simply finding the under-hood box isn't quite enough; you need to pinpoint the exact spot where the fuel pump relay sits within it.

  1. Remove the Cover: The box has a protective plastic cover. Lift the front edge gently to release clips, then lift the cover off entirely. Sometimes it hinges upwards. Place the cover safely aside.
  2. Identify the Lid Diagram: Crucially, the underside of the cover you just removed should contain a detailed diagram. This diagram maps out the location and function of every fuse and relay slot inside the box.
  3. Find Position #2 / "Fuel Pump": Examine this diagram closely. Look for the slot clearly labeled "#2" or "Fuel Pump" (FP). Honda consistently places the fuel pump relay in Position #2 on the 2004 Accord.
  4. Match the Diagram to the Box: Inside the open fuse box, look for the corresponding slot marked "2" or containing the number "2" molded into the plastic base nearby. Relays in the under-hood box are typically arranged in a grid pattern.

Recognizing the Fuel Pump Relay

Relays share a similar physical appearance:

  • Shape: Most are small, square or rectangular black plastic cubes.
  • Pins: They have metal connector pins protruding from the bottom to plug into the slots in the fuse box.
  • Specific Size: The fuel pump relay (and other identical under-hood control relays) is usually a standard small ISO/mini relay format, significantly larger than a fuse but smaller than the main relay.

Since multiple relays often look identical, the label on the box lid diagram and the physical slot number (#2) are the definitive identifiers. Never rely solely on visual similarity between relays; always verify the position.

Symptoms of a Failing Fuel Pump Relay

Understanding when to suspect the relay saves time. A failing fuel pump relay in your 2004 Accord often presents these symptoms:

  1. No-Start Condition (Cranks but Won't Fire): This is the most classic sign. The engine cranks normally, but it doesn't start because the fuel pump isn't being activated to send fuel to the engine. You won't hear the brief whirring sound from the rear (fuel tank area) when the ignition is first turned to "ON" (before cranking).
  2. Intermittent Starting Problems: The car might start fine sometimes and fail to start other times. This is very common as the internal electrical contacts inside the relay wear out or become intermittent due to heat cycles or oxidation. It might start when cold but fail when hot, or vice-versa.
  3. Engine Stalling While Driving: A relay that cuts out unexpectedly while driving will cause the engine to stall immediately as fuel delivery stops. Power steering and brakes become much harder to operate, creating a dangerous situation.
  4. No Fuel Pump Prime Noise: With the ignition key turned to "ON" (the position before cranking), you should normally hear the fuel pump run for about two seconds. If you hear no sound from the rear of the car during this key-on phase, the relay is a prime suspect.

How to Test the Fuel Pump Relay (Basic)

While professional diagnosis involves multimeters, some simple checks exist:

  1. The Swap Test: Find another identical relay in the under-hood box. A common candidate is the radiator fan relay (often position #6) or the A/C compressor clutch relay. They are usually interchangeable for testing. Carefully pull out the suspect fuel pump relay (position #2). Note its orientation. Carefully pull out the identical known-good relay. Install the known-good relay into the fuel pump position (#2). Turn the ignition to "ON." Listen carefully near the fuel tank or the open driver's door for the fuel pump prime sound (approx. 2 seconds). If you hear it now but didn't before the swap, the original relay is likely faulty. If you still don't hear it, the problem could be elsewhere (fuse, wiring, pump itself).
  2. Audible Click Test: Have an assistant turn the ignition key to "ON" while you firmly hold the relay. You might feel and hear a distinct internal "click" at the moment the ignition is turned on, indicating the relay's internal coil is energizing. The absence of this click strongly suggests a relay problem (or no power/control signal reaching it). Note: Feeling a click doesn't guarantee the internal contacts are good, but no click is a strong indicator of relay failure.

Replacing the 2004 Honda Accord Fuel Pump Relay

If testing points to a faulty relay, replacement is straightforward:

  1. Safety First: Turn the ignition OFF. Remove the key.
  2. Access the Relay: Locate the under-hood fuse/relay box and remove the lid as described.
  3. Identify Position #2: Confirm the relay location using the diagram and physical slot marking.
  4. Remove the Old Relay: Firmly grasp the relay in position #2 and pull it straight upwards out of its socket. Avoid excessive rocking or twisting.
  5. Obtain Replacement: Purchase a replacement relay. Crucially, use the correct Honda part number or a high-quality automotive relay specified as compatible. Common Honda part numbers used for the 2004 Accord fuel pump relay include 38435-SDA-A01, 38435-SDA-A02, and 38435-SDA-A03. Ensure any aftermarket relay matches the specs and terminal configuration.
  6. Install the New Relay: Align the new relay correctly over the slot #2 socket. The relay will usually have an orientation guide (like tab vs. notch). Gently but firmly push it straight down until it seats fully.
  7. Test: Turn the ignition key to "ON." You should hear the fuel pump prime for a couple of seconds. Attempt to start the engine. If successful, secure the fuse box lid back in place.

Important Considerations and Potential Confusion

  • Position #2 is Key: Always trust the physical position number and the diagram on your specific box lid. While descriptions like "back row, middle" are sometimes used, variations between trims (LX, EX, V6) can make these unreliable.
  • Main Relay vs. Fuel Pump Relay: Honda Accords are also known for main relay failure, located inside the interior fuse panel (usually under the dashboard). The main relay supplies power to other components, including the fuel pump relay circuit in the under-hood box. Symptoms can overlap. If replacing the under-hood fuel pump relay doesn't solve a crank/no-start, the main relay becomes the next likely suspect.
  • Fuse Check: Before condemning the relay, always check the relevant fuse. For the fuel pump circuit on the 2004 Accord, consult the under-hood fuse box diagram to find the "FI" (Fuel Injection) fuse (often 15A) or sometimes "ECU" fuse, and the under-hood "FUEL PUMP" fuse (typically 15A). A blown fuse will prevent the relay from operating correctly.
  • OEM Recommended: While cheaper generic relays exist, using a genuine Honda or a high-quality automotive-grade relay designed for this application is strongly advised for long-term reliability and safety. Inferior relays can fail prematurely or worse.

When Professional Diagnosis is Needed

While locating and swapping the relay is generally accessible, consider professional help if:

  • Swapping relays doesn't resolve the no-start/stalling issue.
  • The fuel pump prime sound still doesn't occur after relay replacement.
  • You are uncomfortable performing basic electrical checks.
  • You suspect wiring damage or other underlying electrical gremlins. A mechanic has specialized tools to verify power at the relay socket and further back at the fuel pump connector.

FAQs

  1. Is it safe to drive with a bad fuel pump relay?

    • No. If the relay fails intermittently while driving, the engine will stall abruptly. This loss of power steering and brakes can lead to a serious accident. Have the issue diagnosed and repaired immediately. Do not drive the vehicle until the problem is fixed.

  2. How much does a 2004 Honda Accord fuel pump relay cost?

    • Costs vary. A genuine Honda relay typically costs between 70 USD. High-quality aftermarket relays can range from 30+ USD. It's worth investing in a known-reliable brand.

  3. Can I bypass the relay to start the car?

    • While possible using jumper wires to manually send power to the fuel pump circuit, this is strongly discouraged. It bypasses crucial safety features controlled by the engine computer (ECU/PCM) and can damage the pump or wiring if done incorrectly or left connected while driving. It's only useful for brief, controlled testing by experienced individuals to isolate the problem.

  4. The relay clicks, but the pump doesn't run. What now?

    • A clicking relay indicates the internal coil is working and receiving the signal to turn on from the ECU/PCM. However, it doesn't guarantee the high-current contacts inside the relay are good. It could still be a faulty relay. Otherwise, the problem lies downstream: a blown fuse, wiring damage between the relay and the fuel pump, a faulty fuel pump inertia cutoff switch (though less likely to cause a total no-pump), or a failed fuel pump itself.

  5. Is there another relay location besides under the hood?

    • No. For the 2004 Honda Accord specifically, the fuel pump relay resides only in the under-hood fuse/relay box in position #2. There is no separate relay box elsewhere for this component. Any secondary interior fuse panel contains different relays (like the main relay).

Knowing the precise location of the fuel pump relay in position #2 of the 2004 Honda Accord's under-hood fuse box empowers you to perform efficient troubleshooting for a common cause of no-start conditions. By understanding the symptoms, performing simple swap tests, and replacing the relay when necessary, you can often restore your Accord's drivability quickly and cost-effectively. However, remember that electrical issues can cascade; if the problem persists after relay replacement, professional diagnostics targeting the fuel pump circuit's power supply (fuses, main relay, wiring) or the fuel pump itself become essential. Prioritize safety – if you're unsure about any step, consult a qualified mechanic.

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