1999 Acura Integra Fuel Pump Relay Location: Find & Fix It Fast

For owners of the popular 1999 Acura Integra experiencing engine start-up issues, the fuel pump relay – officially known as the PGM-FI Main Relay – is very likely the culprit and is located under the dashboard on the driver's side, specifically behind the lower trim panel near the hood release lever and to the right of the parking brake pedal. This crucial relay controls power to the fuel pump and the engine's fuel injectors. If it fails, your Integra either won't start at all or will stall unexpectedly. Knowing its precise location and how to test it is essential for quick diagnosis and repair. Understanding symptoms and verifying the relay are the critical next steps after locating it.

Understanding the Fuel Pump Relay's Job
The fuel pump relay acts like an electrically controlled switch. When you turn the ignition key to the "ON" position (before cranking), the engine control unit (ECU) sends a brief signal to the relay's coil. This energizes the coil, pulling internal contacts closed. This closed circuit then provides main battery power directly to the fuel pump motor. The pump runs for a few seconds to pressurize the fuel system. During engine cranking and operation, the ECU keeps the coil energized, maintaining power to the pump. A relay is used because the fuel pump draws a relatively high electrical current. Using the ECU to directly switch that current would damage the ECU's sensitive circuits. The relay handles the heavy lifting using a low-power signal. Failure of this relay means no power reaches the fuel pump, leading to no fuel pressure and a failure to start or run.

Recognizing Symptoms of a Bad Fuel Pump Relay in Your 1999 Integra
Suspect the fuel pump relay if you experience any of these common issues:

  1. Complete Failure to Start (No Cranking Noise Change): The engine cranks normally when you turn the key, but it never fires up. You don't hear the characteristic 2-3 second "whirring" sound of the fuel pump priming when you first turn the ignition to "ON". This is the most classic sign.
  2. Engine Stalls While Driving: The car starts and runs initially but suddenly and unexpectedly stalls while driving, especially after it's warmed up (a common failure mode as the relay heats up). It may restart after cooling down briefly, only to stall again later.
  3. Hard Starting When Warm: The engine starts fine when cold, but after shutting it off once it's warmed up (like stopping for gas), it cranks but refuses to start again until it cools down significantly.
  4. Intermittent Starting Problems: Sometimes the car starts perfectly, other times it exhibits the "no start" symptoms described above, seemingly at random. This points towards an internal relay connection problem.

Locating the 1999 Acura Integra Fuel Pump Relay (PGM-FI Main Relay)
This is the core information:

  1. Position: Sit in the driver's seat. Look down at the lower section of the dashboard, near your knees and feet, specifically focusing on the area to the RIGHT of the parking brake pedal and just LEFT/BEHIND the hood release lever.
  2. Access Panel: You will see a rectangular or trapezoidal plastic access panel molded into the lower dashboard trim. This panel is usually secured with one or two Phillips head screws. In some models, it might have plastic clips or hooks instead of screws at the bottom.
  3. Tools Needed: A flashlight is essential. A Phillips screwdriver (likely #2) is needed if screws are present. A small flat-head screwdriver can help gently pry clips if needed.
  4. Remove the Panel:
    • Locate the screw(s) typically at the top or side of the panel. Unscrew them completely and set them aside safely.
    • If there are clips at the bottom, carefully pry the panel away from the dash structure, starting from the bottom, using your fingers or the flat-head screwdriver gently to avoid breaking clips. Pull the panel downward and toward you.
  5. Identify the Relay Box: Behind this panel, you will see a rectangular relay box mounted vertically or at a slight angle. This box is typically black or grey plastic and houses several relays and often some fuses.
  6. Identify the Specific Relay: The fuel pump relay is the PGM-FI Main Relay. Within the relay box, look for the relay unit itself. Key identifiers:
    • Shape/Size: It will be a small, roughly cube-shaped (about 1.5" x 1.5" x 1") component, usually black.
    • Connector: It plugs into a socket via pins on its bottom. The socket for the PGM-FI Main Relay in the 1999 Integra typically has 9 pins arranged in a specific pattern (often noted on the relay body or the socket itself). Note: Some sources describe it as a 10-pin connector, but the 9-pin is standard for this location/year.
    • Labeling: The relay itself or the relay box diagram (often printed on the inside of the access panel cover you removed or molded onto the relay box itself) will likely be labeled "PGM-FI", "Main", or "Fuel Pump". Do not confuse it with other relays like the Cooling Fan Relay or Fuse Relay. The PGM-FI Main Relay combines the functions for the fuel pump and the ECU/injectors in one unit. If you can find the diagram, match the relay position to the "PGM-FI MAIN" label.

(Important Safety Step) Disconnect the Battery Before Proceeding
BEFORE touching the relay or its wiring, disconnect the NEGATIVE terminal of your car's battery. Place the disconnected cable somewhere it cannot accidentally touch the battery terminal. This prevents accidental electrical shorts or sparks while you handle the components behind the dash, protecting both you and your car's sensitive electronics.

Physically Removing the Fuel Pump Relay

  1. Visual Confirmation: Reconfirm you have the correct relay using the descriptions above (location near parking brake/hood release, PGM-FI Main label, 9-pin connector).
  2. Grasp Firmly: The relay will be seated firmly into its socket. Grasp it securely at the base, getting a good grip with your fingers.
  3. Pull Straight Out: Apply firm, steady pressure directly straight back away from the socket. Avoid rocking or twisting excessively, as this can damage the relay's pins or the socket. It might take a reasonable amount of force to overcome the friction. The relay should release smoothly once the pins disengage.

Testing the 1999 Integra Fuel Pump Relay
Do NOT skip testing! Other issues (like a bad fuel pump, blown fuse, or wiring fault) can mimic a relay failure. Testing confirms the diagnosis. Methods:

Method 1: The "Bench Test" (Recommended - Safer & More Accurate)

  1. Find a Helper: You'll need someone to turn the ignition key while you listen/feel the relay.
  2. Listen and Feel: Hold the relay firmly in your hand. Have your helper turn the ignition key to the "ON" position (but do not crank the engine).
  3. Feel for the Click: Working Relay: You should feel and hear a distinct, solid "CLICK" within the relay about 1-2 seconds after turning the key to "ON". This is the internal electromagnet pulling the contacts closed. Faulty Relay: You feel/hear nothing, a faint buzz, a weak click, or multiple erratic clicks. This usually indicates a failed relay coil or internal contact problem. Note: Feeling the click confirms the coil circuit is activating, but not necessarily that the high-current contacts are good. However, a lack of click strongly points to a relay problem.
  4. Listen to Pump: Simultaneously, have your helper listen carefully near the rear of the car. They should also hear the fuel pump run for those 2-3 seconds. If the relay clicks but the pump doesn't run, you likely have a bad pump, wiring issue, or fuse problem.
  5. Smell: Give the relay a careful sniff. A strong burnt electrical smell strongly indicates the relay has overheated and failed.

Method 2: The "Swap Test" (If Another Identical Relay Exists)

  • Identify Identical Relays: Look carefully within the relay box under the dash. Other relays might be identical in shape, size, and pin configuration to the PGM-FI Main relay (though less likely in the interior box). A common candidate is sometimes the Cooling Fan Relay, but VERIFY EXACT MATCH VISUALLY. Relays from the underhood fuse box are usually different types. Crucially: The replacement relay must match exactly (same part number, pin count and configuration). Swapping a non-identical relay risks damage.
  • Swap: If you find an exact match in a non-critical system (e.g., maybe a rear window defogger relay, assuming it's identical), carefully swap the suspect PGM-FI Main Relay with this known good relay.
  • Test Operation: Turn the ignition to "ON" - does the fuel pump now prime? If so, your original relay is bad. If not, the problem likely lies elsewhere (pump, fuse, wiring). Remember to swap the relays back afterward if the test is negative!

Method 3: The "Jumper Wire Test" (Advanced - Riskier)

  • Use with Caution! This method forces power directly to the fuel pump, bypassing the relay. Mistakes can cause electrical shorts. Only attempt if comfortable. Have a fire extinguisher nearby.
  • Tools: Need a fused jumper wire kit OR a piece of heavy gauge (12-14 AWG) wire with alligator clips and a 15-20 amp fuse in-line. Regular wire won't be safe.
  • Locate the Pump: The fuel pump connector is typically near or on top of the fuel tank, accessed through the trunk or under the rear seat. Consult a service manual for the exact location. This is complex on the Integra without specifics.
  • Jumper: Identify the power wire (often heavy gauge, Black/Yellow on the Integra pump connector) and ground. Disconnect the pump connector. Clip your fused jumper between the pump's positive terminal and the battery POSITIVE. Carefully touch the pump's ground wire terminal to a good chassis ground. SAFETY: Fuel vapors! Sparks can ignite them! Do this with good ventilation. Test: If the pump runs solidly when jumped, the pump itself is likely okay, pointing back to the relay, wiring, or ECU. Note: This doesn't directly test the relay, only proves the pump can run. The dash relay methods 1 or 2 are generally safer and more diagnostic for the relay itself.

Testing the Easy Things First: Fuses
Before condemning the relay, always check the relevant fuses! A blown fuse will also prevent the fuel pump from running and is much easier to fix. Location: Your 1999 Integra has two main fuse boxes.

  1. Underhood Fuse/Relay Box: Open the hood. The large black box near the battery contains fuses and relays.
    • Check Fuse: Locate fuse #20 (a 15 Amp fuse) in the underhood box. This is often labeled as "PGM-FI" or "ECU". Pull it out and inspect the metal strip inside - it should be intact. Replace with another 15A fuse if blown. Also, check fuse #6 (15A Back-Up/Radio).
  2. Dashboard Fuse Panel: Located lower driver's side dash, usually accessible by opening the driver's door (sometimes requires a small access cover to be flipped down).
    • Check Fuse: Locate fuse #13 (a 7.5 Amp fuse), often labeled "Fuel Pump" or "ECU". Inspect and replace if blown.

Purchasing the Correct Replacement Relay
Using the correct component is crucial for reliability.

  1. OEM Part Number: The genuine Acura/Honda part number for the PGM-FI Main Relay in the 1999 Integra is 39400-S04-A01. Taking your old relay to the dealer parts counter ensures you get the right one.
  2. Aftermarket: Major auto parts stores will have equivalent relays under brands like Standard Motor Products (SMP), BWD, or Omron. Ask for the fuel pump relay/PGM-FI Main Relay for a 1999 Acura Integra. Ensure the replacement physically matches the old one (shape, pin count, pin configuration). Quality Matters: Relays are cheap; avoid the absolute cheapest unknown brands. Stick with recognized aftermarket or genuine OEM.
  3. Get the Relay: Purchase the new relay.

Reinstalling the Fuel Pump Relay

  1. Orient Correctly: Look closely at the relay and the socket. You will see guides or tabs that ensure it only plugs in one way. Match these. Do not force it; it should seat easily if oriented correctly.
  2. Push Firmly: Align the pins carefully. Press the relay firmly and straight into the socket until it seats completely. You should feel it click into place.
  3. Reattach Access Panel: Replace the dashboard access panel. Secure any screws you removed. Snap clips back into place if applicable. Ensure it's flush and secure.
  4. Reconnect Battery: Reattach the NEGATIVE battery terminal and tighten it securely.

Confirm the Fix

  1. Turn the ignition key to the "ON" position. You should immediately hear the fuel pump run for approximately 2-3 seconds to prime the system. This is the key sign the new relay is working!
  2. Now attempt to start the engine. If the symptoms (non-start, stalling) have been resolved, the relay replacement was successful.

"My Relay Isn't There!" - Troubleshooting Location Issues
Occasionally, previous owner repairs or model variations might cause confusion:

  • Double-Check Location: Re-read the location description: Behind the panel near the parking brake pedal and hood release lever on the driver's side. Ensure you removed the correct panel (it's not the door sill trim or kick panel).
  • Verify Year & Trim: The PGM-FI Main Relay location described is consistent for all 1999 Acura Integra models (LS, GS-R, Type-R). 1994-1997 models sometimes have it behind the glove box (especially in Canada, though inconsistent). 1998-2001 models firmly place it behind the driver's knee panel as described.
  • Aftermarket Modifications: Previous owners might have relocated the relay due to damage, or incorrectly installed an aftermarket security system that affects the fuel pump circuit. Trace the original fuel pump wiring back from the relay box socket if the relay seems missing.
  • Terminal Confusion: Focus on finding the relay box under the dash, then identify the relay by its function label/part number, not just the socket. Sometimes the actual relay has been removed but the socket remains.
  • Professional Help: If you absolutely cannot locate the relay following these steps, consult a professional mechanic or a dedicated Acura Integra repair forum with photos of your specific under-dash area.

When Replacement Doesn't Solve the Problem
If you replaced the relay and the fuel pump still doesn't prime/run:

  1. Recheck Work: Did you reconnect the battery? Is the new relay fully seated? Double-check fuse #20 (underhood) and #13 (dash) again.
  2. Faulty New Part: While rare, new relays can be defective. Try the "Bench Test" on the new relay while you have the old one available for comparison.
  3. Fuel Pump Failure: If the relay bench test showed it was clicking and you still don't hear the pump run (even with the new relay), the fuel pump itself is likely dead. Diagnose this with the "Jumper Test" described earlier (or a fuel pressure gauge) if comfortable, or seek professional diagnosis.
  4. Wiring Harness Damage: Corrosion, rodent damage, or physical pin damage in the relay socket or wiring harness (especially under the dash or near the ECU) can interrupt power or signal. Visually inspect wiring as best as possible. Testing continuity requires a multimeter and wiring diagram knowledge. Disconnect the battery before probing wires.
  5. Faulty Main Relay Socket: The socket the relay plugs into can develop loose, corroded, or burnt terminals, preventing good contact. Inspect the socket carefully when the relay is removed. Look for melted plastic, discoloration, or bent pins inside. Replacing the socket harness is more involved.
  6. ECU Failure: A complete ECU failure (rare) or a failure specifically in the circuit controlling the relay coil signal would prevent the signal from ever reaching the relay. This requires advanced diagnosis or ECU replacement. Usually, other significant engine problems would also be present.

Why Use Genuine or High-Quality Replacement Parts
While aftermarket relays are functional, experience shows:

  1. Longevity: Genuine Honda/Acura relays and high-quality aftermarket brands often demonstrate significantly better long-term reliability compared to generic, ultra-cheap alternatives. The PGM-FI main relay is critical; replacing it with a low-quality part can leave you stranded again prematurely.
  2. Precise Specifications: OEM relays are built to exacting electrical standards. Cheap clones might have slightly weaker coil magnets or less durable contacts that fail under heat or load.
  3. Correct Pin Fitment: Poorly made clones might have pins that are slightly undersized or misaligned, leading to poor electrical contact in the socket, causing intermittent problems or premature failure.
  4. Avoid the Hassle: Spending a few extra dollars on a known brand (SMP, Omron, BWD, or OEM) buys peace of mind and avoids the frustration of a quick repeat failure.

Key Takeaways & Final Advice
Locating and replacing a bad PGM-FI Main Relay (fuel pump relay) in your 1999 Acura Integra is a common and manageable repair:

  • Location: Behind driver's knee panel trim, near parking brake pedal/hood release (driver's footwell).
  • Symptoms: No-start (with crank, no pump sound), engine stalls when warm, hard starting when hot.
  • Test: Confirm pump doesn't prime with key on, bench test relay for audible/feelable click. Check fuses (#20 underhood, #13 dash).
  • Replacement Part: Use genuine Acura 39400-S04-A01 or a reputable aftermarket equivalent.
  • Safety: Always disconnect battery negative terminal before electrical work.

By following these detailed steps, you can accurately diagnose a fuel delivery problem caused by the relay and restore your 1999 Integra to reliable operation. Prioritize safety, double-check your work, and invest in a quality replacement component. If the repair proves too challenging or diagnostic uncertainties remain, consulting a trusted automotive technician ensures the job is done correctly, protecting your investment and ensuring your safety on the road. Knowing your car's anatomy and being prepared can transform a frustrating no-start situation into a simple 20-minute fix.

Back to blog