1991 Toyota Corolla Fuel Pump Relay Location: Your Essential Guide

The fuel pump relay in your 1991 Toyota Corolla is located inside the vehicle's passenger compartment, specifically mounted on the fuse block attached to the lower left kick panel near the driver's feet, just below and slightly forward of the steering column.

Finding the fuel pump relay is a common task when diagnosing a no-start or fuel delivery issue with this generation of Corolla. Understanding exactly where it is and how to access it is crucial for effective troubleshooting. This guide provides comprehensive, step-by-step details based on official repair manuals and extensive hands-on experience with these vehicles.

Understanding the Role and Criticality of the Fuel Pump Relay

The fuel pump relay is a vital electronic switch within your Corolla's fuel delivery system. Its primary function is to control the electrical power supplied to the fuel pump motor.

  • Why It's Switched: The fuel pump requires significant electrical current (amperage) to operate effectively, far more than most dashboard switches or the Engine Control Unit (ECU) can safely handle directly. The relay acts as a high-current switch controlled by a low-current signal.
  • How It Works (Simplified):
    • When you turn the ignition key to the "ON" or "Start" position, the Engine Control Unit (ECU) or a dedicated circuit sends a small electrical signal to the relay's control coil (Terminal 1).
    • This signal creates a magnetic field, pulling internal switch contacts together inside the relay.
    • These closing contacts bridge the circuit between the high-current power source (usually a fusible link or maxi-fuse from the battery, entering via Terminal 3) and the fuel pump itself (output via Terminal 2).
    • Once the engine is running, the relay typically stays energized as long as the ignition is on and the ECU receives a signal from the crankshaft position sensor indicating the engine is turning. If the engine stalls, the ECU cuts power to the relay to stop the pump as a safety measure.
  • Why Location Matters: A malfunctioning fuel pump relay prevents power from reaching the fuel pump entirely, mimicking a dead pump. Quickly locating and testing the relay is often the first step in diagnosing a no-fuel condition before more complex tasks like accessing the tank pump.

Detailed Location: Finding the Relay Behind the Kick Panel

Follow these precise steps to locate the 1991 Toyota Corolla's fuel pump relay. Refer to accompanying high-resolution photos and diagrams for visual confirmation.

  1. Prepare for Access:
    • Park your Corolla on a level surface, engage the parking brake firmly, and place the transmission in Park (Automatic) or Neutral with the parking brake engaged (Manual).
    • Turn the ignition key fully to the "OFF" position and remove it.
    • For safety and ease of access, open the driver's door fully.
  2. Locate the Driver's Side Kick Panel:
    • Sit in the driver's seat. Look down towards the area where your left foot rests near the floor, against the wall of the car beneath the dashboard. This area, extending upwards towards the hood release lever, is the lower left kick panel.
    • The kick panel is a plastic trim piece covering the fuse/relay block and wiring harnesses.
  3. Identify the Panel Release Clips:
    • The kick panel is secured by several plastic clips or retaining screws located along its edges. On the 1991 model, clips are more common.
    • Feel along the top edge of the panel, approximately where the dashboard meets it, and near the hood release lever (if present). You may also find clips along the forward (front of the car) and lower edges.
  4. Remove the Kick Panel:
    • Using your fingers, gently pry the kick panel away from the metal body of the car where you located the clips/screws. Start near the hood release or top edge.
    • Apply firm, even pressure directly outwards (away from the interior). Avoid jerking or excessive force to prevent breaking the fragile plastic clips or the panel itself.
    • If you encounter a fastener, such as a Phillips head screw near the hood release handle (on some models), carefully remove this first.
    • Once all fasteners are released, lower the panel and rotate it slightly to disengage it from the dash lip. Carefully remove it from the footwell. Be mindful of wires potentially attached to accessories like footwell lights.
  5. Locate the Fuse/Relay Block:
    • With the kick panel removed, you will see a rectangular or square-shaped plastic housing securely mounted to the metal structure of the car's firewall or inner fender. This is the interior fuse and relay block assembly. It will contain numerous fuses and several relays.
    • Note the presence of other wires in this area; avoid disturbing them unnecessarily.
  6. Identify the Fuel Pump Relay:
    • Look Directly at the Fuse/Relay Block: The relays are typically black plastic cubes plugged into sockets on this block. They are distinct from the smaller, blade-style fuses.
    • Consult the Fuse Box Diagram: On the inside surface of the removed kick panel (very common location), or sometimes printed on a sticker affixed directly to the fuse/relay block cover, you will find a diagram. This diagram labels each fuse and relay position numerically or alphabetically and lists their functions. This is the most reliable way to identify the relay.
    • Diagram Identification: Look for labels such as "FUEL PUMP," "FP," "EFI," or "Circuit Opening Relay." The EFI Main Relay is also located nearby and plays a crucial role in fuel injection power but is distinct from the fuel pump relay. Verify the label explicitly mentioning the fuel pump. On the 1991 Corolla, it is clearly labeled as such.
    • Typical Relay Position: While the exact position can vary slightly depending on specific trim (e.g., DX, LE) and fuse block revisions, the fuel pump relay is commonly found near the top or center of the fuse block assembly, often adjacent to the EFI Main Relay and possibly headlight relays. Count the sockets and slots if necessary.
    • Relay Characteristics: The fuel pump relay itself is generally a standard-sized, black, cube-shaped component, typically measuring around 1 inch (25mm) per side. It will have either 4 or 5 metal terminal pins (prongs) protruding from the bottom. The Toyota part number is often molded into the top plastic casing (e.g., 28300-XXXXX).

Verification: Confirming You Have the Correct Relay

Before proceeding with testing or replacement, double-check you have identified the correct relay:

  1. Match Label to Diagram: Ensure the relay socket identified on the fuse box diagram is labeled for the fuel pump.
  2. Physical Check: Trace the wire color codes if possible (using a reliable source like a factory wiring diagram – wires feeding the pump often include a Black-Yellow or Yellow-Black tracer). Power to the fuel pump originates at the relay output terminal (Terminal 2).
  3. Operation Test (Basic): If your car exhibits a no-fuel problem, carefully listening can help. Turn the ignition key to the "ON" position (do not start the engine). You should hear a distinct audible click from the fuel pump relay for 1-2 seconds as it momentarily energizes to prime the system. A lack of this audible click suggests a potential relay or control circuit issue. Caution: Ensure you are in a quiet environment and listen near the driver's footwell area.

Symptoms of a Failed Fuel Pump Relay (1991 Corolla Specific)

Understanding when the relay might be the culprit helps prioritize diagnosis. Watch for these symptoms:

  1. Engine Cranks But Fails to Start: The most common indicator. The starter turns the engine over normally, but the engine never catches and runs. This indicates no fuel is being delivered to the engine cylinders.
  2. No Audible Fuel Pump Prime: As mentioned above, no brief "whirring" sound from the rear of the car (where the fuel pump is in the tank) and no audible click from the driver's footwell relay when turning the ignition key to "ON."
  3. Intermittent Starting Problems: The car might start and run normally sometimes, but other times fails to start. Often triggered by temperature (hot engine bay affecting relay components) or vibration. Faulty solder joints or thermal failures inside the relay cause this.
  4. Sudden Engine Stalling While Driving: Although less common than a complete failure to start, a relay that fails while the engine is running will cause immediate and complete loss of fuel pressure and engine stall. It will not restart.
  5. No Power to the Fuel Pump Test Connector: The 4A-FE engine in the 1991 Corolla has a specific diagnostic connector near the fuse box under the hood, often labeled "+B" and "FP." Applying battery voltage to the "FP" terminal should directly power the fuel pump if the relay and circuits are good. If you get no power at the pump test connector when the key is "ON" (indicating the ECU control circuit isn't activating the relay) but applying power via the test connector makes the pump run, points strongly to a control circuit or relay failure. Warning: Testing the pump using this connector requires specific knowledge; consult a proper diagnostic procedure.

Testing the 1991 Toyota Corolla Fuel Pump Relay

Before replacing, confirm if the relay is faulty. Here’s how to test it effectively:

Safety Precautions:

  • Turn the ignition key OFF and remove it.
  • Consider disconnecting the negative (-) battery terminal for absolute safety, especially if handling the relay near the block.

Tools Needed:

  • Digital Multimeter (DMM) capable of measuring DC Voltage and Resistance (Ohms).
  • Jumper wires with appropriate probes or clips.

Method 1: Testing Relay Coil (Control Circuit) - Resistance Check

  1. Carefully remove the relay from its socket by pulling it straight out. Avoid bending pins.
  2. Identify the relay control circuit terminals. These connect to the coil inside. On standard automotive ISO relays (common on Toyotas), these are usually Terminal 85 and Terminal 86. The fuel pump relay is likely an ISO micro relay format. Consult the fuse block diagram or a relay terminal identification guide if pins aren't labeled.
  3. Set your multimeter to measure resistance (Ohms, Ω).
  4. Place the multimeter probes firmly on the control circuit terminal pins (e.g., 85 & 86).
  5. Interpret Reading:
    • You should measure a resistance value. A good coil will typically show between 50Ω and 150Ω. Example: A reading of 70Ω or 120Ω would be normal.
    • An infinite resistance (OL or overload) indicates an open coil – the coil windings are broken. The relay will not function.
    • A zero or very low resistance (near 0Ω) indicates a shorted coil – the coil is internally damaged. The relay may malfunction or blow fuses.
    • An out-of-spec resistance (e.g., significantly higher or lower than typical automotive relays) indicates a problem. Compare against the relay specs if known.

Method 2: Testing Relay Switch Contacts (Load Circuit) - Resistance Check

  1. Identify the relay load circuit terminals. These connect to the high-current switch. On ISO relays, these are usually Terminal 30 (Battery Constant Power Input) and Terminal 87a or 87 (Output to Fuel Pump). Fuel pump relays are typically SPDT (Single Pole Double Throw) or SPST (Single Pole Single Throw). 5-pin relays often have Terminal 87 (Normally Open - powers pump) and 87a (Normally Closed - unused or alternative circuit). The 1991 Corolla uses the normally open terminal. Identify Terminals 30 and 87 from the fuse box diagram/wiring schematic.
  2. Set your multimeter to measure resistance (Ohms, Ω).
  3. Normally Open (N/O) Contact (Terminal 30 to 87):
    • With the relay unenergized (just sitting on the bench), place probes on Terminal 30 and Terminal 87.
    • You should measure infinite resistance (OL) – the switch contacts are open.
    • Apply a small battery voltage (e.g., from a 9V battery) across the control terminals (Terminals 85 and 86). You should hear/feel the relay click.
    • While voltage is applied across the coil, measure resistance again between Terminal 30 and Terminal 87. You should now measure low resistance (near 0Ω) – the switch contacts have closed.
    • Release the coil voltage; the contacts should open again (reading OL).
    • Failure to close (still OL) indicates burned, pitted, or stuck-open contacts.
    • Failure to open (still 0Ω even without coil power) indicates welded or stuck-closed contacts.

Method 3: Testing Relay Power & Ground In The Vehicle

  1. Caution: Ensure ignition is OFF. Reinstall the relay into its socket.
  2. Identify Key Terminals: Know which socket terminals correspond to: Ground (typically 85 or 86 - confirmed with diagram), Power from ECU/Ignition Switch (typically the other control terminal - 86 or 85), Battery Constant Power (30), and Fuel Pump Output (87).
  3. Voltage Testing Ground & Control Power:
    • Set multimeter to DC Volts (20V range).
    • Connect multimeter Black probe to a known-good ground point on bare metal chassis.
    • Turn ignition key to "ON" position (do not crank).
    • Touch multimeter Red probe to the ECU/Ignition Control terminal socket (where pin 85 or 86 connects, specifically the one fed by the ignition/ECU).
      • Expected: +12V to +14V (battery voltage).
      • Failure: 0V indicates a problem in the ignition switch, ECU, or wiring from ignition/ECU to the relay socket.
    • Touch multimeter Red probe to the Ground terminal socket (where the other pin 85/86 connects).
      • Expected: Very low voltage (< 0.5V), confirming ground path integrity back to the battery negative. Alternative: With ignition ON, set meter to Ohms mode (power OFF!), probe this socket terminal and a good chassis ground – should read near 0Ω. Take care with meter settings.
  4. Voltage Testing Power Input (Terminal 30):
    • Touch Red probe to the Battery Power Input socket terminal (Terminal 30).
    • Expected: +12V constant battery voltage (regardless of key position, unless the main battery fuse/link is blown).
    • Failure: 0V indicates a blown main fuse, fusible link, or broken wiring.
  5. Voltage Testing Relay Output (Terminal 87) - With Control Signal:
    • With ignition still "ON," touch Red probe to the Fuel Pump Output socket terminal (Terminal 87).
    • Expected: +12V (or close to battery voltage) as the relay should be momentarily energized.
    • Failure: 0V indicates either:
      • Control circuit fault (already tested) OR
      • The relay itself is faulty (switching contacts) despite getting control power/ground OR
      • Blown fuel pump fuse (located elsewhere - check fusebox diagram).
      • Critical: If voltage is present briefly but disappears, that's normal ECU behavior; it stops sending the signal after ~2 seconds unless engine is cranking/running.

Replacing the 1991 Toyota Corolla Fuel Pump Relay

  1. Identify Correct Replacement:
    • Part Number: Use the number molded onto the top of the old relay (e.g., 28300-XXXXX). This is the most accurate way.
    • OEM vs. Aftermarket: Toyota OEM (Denso) relays offer guaranteed compatibility. High-quality aftermarket brands (e.g., Bosch, Standard Motor Products - SMP) also provide reliable alternatives. Match the terminal pin count and configuration precisely (4 or 5 pins).
    • Parts Sources: Toyota dealership parts counter, reputable auto parts stores (NAPA, AutoZone, Advance Auto Parts, O'Reilly), or trusted online retailers.
  2. Purchase: Obtain the correct relay.
  3. Installation:
    • Ensure ignition is OFF and key removed.
    • Ensure you have proper access to the fuse/relay block (kick panel removed).
    • Locate the relay socket.
    • Carefully align the new relay's terminal pins with the socket slots, ensuring the orientation matches the old one (a missing or offset pin acts as a key).
    • Push the relay firmly straight down into the socket until it is fully seated and latched. You should feel and hear it click into place.
    • Reinstall the driver's side kick panel. Align it correctly and snap the plastic clips back into place, or reinstall any screws that were removed near the hood release handle. Ensure the panel is flush and secure.
  4. Verification: Turn the ignition key to the "ON" position. You should now hear the distinct, momentary click from the relay and the brief whirr of the fuel pump priming at the rear of the car. Try starting the engine. If it starts and runs normally, the replacement was successful.

Prevention: Tips for Long-Term Reliability

While relays are generally reliable, consider these tips:

  1. Protect from Elements: Ensure the kick panel is securely installed to prevent excessive moisture or dirt ingress onto the fuse/relay block. Corrosion causes failures.
  2. Quality Parts: Use high-quality OEM or reputable aftermarket relays.
  3. Address Underlying Issues: Persistent failures could indicate wiring problems (chafing, corrosion in the socket, short circuit) or a failing component drawing excessive current. Diagnose fully.
  4. Avoid Overload: While rare, ensure no aftermarket equipment is incorrectly tapping into the fuel pump circuit, overloading the relay contacts.

Troubleshooting Flowchart Summary (For No Fuel Delivery)

Use this logical sequence when facing a no-start scenario potentially caused by fuel delivery failure:

  1. Verify Symptoms: Engine cranks normally but does not start? No fuel pump prime sound? Check engine fuse and relevant fusible links under the hood first.
  2. Listen for Relay Click: Turn key to "ON" – listen/feel for fuel pump relay click in driver's footwell. Hear Click?
    • YES: Focus downstream: Fuel pump fuse -> Fuel pump power -> Fuel pump ground -> Fuel pump itself. Use the diagnostic connector under the hood to test pump operation directly.
    • NO: Focus upstream and relay:
      • Access relay location (remove kick panel).
      • Check if relay physically feels abnormally hot.
      • TEST: Check control circuit power at relay socket (Terminal 85/86 one should be +12V Key ON, other good ground?).
      • Check Power Input: Test battery power at Terminal 30 (constant +12V?).
      • Swap Test: If a compatible relay is nearby (like the horn relay which is also momentary), carefully swap it into the fuel pump socket. Caution: Verify compatibility first. If the problem moves (fuel pump primes after swap), the original relay is bad. Not Recommended: Swapping EFI Main Relay or other critical relays is not advisable due to different characteristics and potential failure modes.
      • If power/ground are good, TEST/REPLACE the relay.
  3. Check Fuel Pump Fuse: This is a separate fuse, often located in the main engine bay fuse box or the interior fuse block. Consult the specific diagram for your 1991 Corolla. A blown fuse downstream of the relay prevents power reaching the pump even if the relay is working.

Locating and diagnosing the fuel pump relay in your 1991 Toyota Corolla is a manageable DIY task with the precise information provided here. Remember the key location: behind the driver's side kick panel, mounted on the fuse block near your left foot. By understanding its function, symptoms of failure, testing procedures, and replacement steps, you can efficiently restore your Corolla’s reliable operation without unnecessary expense or guesswork. Always prioritize safety when working on any vehicle electrical systems.

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