1986 Toyota Pickup Fuel Pump Relay Location – Practical Guide

The fuel pump relay in a 1986 Toyota Pickup (Hilux) is located within the main engine compartment fuse and relay box. This box is typically found on the driver's side (left side for USA models), mounted near the firewall/bulkhead behind the battery and close to the brake master cylinder.

Finding and identifying this crucial component is essential if your truck exhibits classic symptoms of a failing fuel pump circuit: difficulty starting (especially when warm), intermittent stalling, or the engine cranking but not firing. Here’s the detailed breakdown:

1. Precise Relay Position within the Fuse Box:

   • Open the hood and locate the rectangular black plastic box mounted vertically or at a slight angle on the driver's side inner fender. It's behind the battery and adjacent to the brake fluid reservoir/master cylinder.
   • Release the Box Cover: Unclip the cover by pressing on the small tabs (usually on the front and sides) and lift it away. Place it somewhere safe.
   • Identify the Fuel Pump Relay: Inside the box, you'll see a cluster of relays and fuses. The fuel pump relay is one of the larger cube-shaped relays. On most 1986 pickups, it shares a row near the center or bottom with other similar-sized relays like the EFI Main Relay.
   • Look for Labels: Inspect the underside of the removed cover. If you're lucky, it will have a diagram clearly labeled "Fuel Pump" or "Fuel Pump Relay." This is the clearest confirmation. If the cover lacks a label or it's faded, proceed to identification based on position and testing.
   • Standard Relay Orientation: If labeled diagrams are unavailable, note that Toyota often arranged relays consistently within these boxes. Focus on the row of larger relays. The fuel pump relay is often positioned alongside the EFI Main relay in this cluster. Compare your relay positions to trusted reference pictures online specific to the 1986 year and pickup model if possible (refer to repair manuals or reputable forums like Toyota Nation).

2. Visual Identification of the Fuel Pump Relay:

   • Appearance: It is typically a black plastic cube, approximately 1 inch square. Older relays might look slightly yellowed or cracked.
   • Terminals: It has four electrical terminals (metal pins) protruding from its base. These correspond to two control coil wires and two switched load wires connecting the battery power source to the fuel pump.
   • Critical Detail - "EFI Relay" vs. Fuel Pump: Be Aware! The most common confusion point. For fuel-injected 22R-E engine models (most common in 1986), the relay explicitly controlling the fuel pump circuit is actually called the "Circuit Opening Relay" (COR) or is part of this function within the system. It often sits adjacent to the main EFI relay or may share similar naming conventions on a label diagram. Think of both the EFI Main Relay and the Fuel Pump/COR relay operating closely together for fuel system operation.
   • Contact vs. Relay Style: Avoid confusion with fuse types within the same box. Fuses are flatter with visible metal strips across the top. Relays are distinct cube units snapped into plastic sockets.

3. How to Test if You Found the Correct Relay (Symptom Simulation):

   • With the ignition OFF, carefully remove the suspected fuel pump relay.
   • Turn the ignition key ONLY to the "ON" position (do not crank the engine). Listen carefully near the fuel tank filler neck area.
   • You should normally hear the fuel pump "whirring" for a brief 1-2 seconds to prime the system at Key ON.
   • Result Interpretation: If you heard the pump prime sound before removing the relay but do NOT hear it after removing the relay and turning Key ON, you have very likely removed the correct fuel pump relay.
   • Re-installation: Press the relay firmly back into its socket until fully seated.

4. Understanding Why the Fuel Pump Relay Matters:

   • This small but vital component acts like a heavy-duty electronic switch. It allows the low-current signal from the ignition switch or ECU to control the high electrical current needed to run the fuel pump motor. Without the relay carrying the load, wiring and switches would overheat and fail prematurely.
   • Failure Triggers: Common causes of relay failure include age-related deterioration of internal electrical contacts, exposure to excessive engine heat over decades, corrosion on terminals, or simple wear and tear. Intermittent contact issues inside the relay are frequent failure modes.

5. Symptoms Pointing Towards a Bad Fuel Pump Relay:

   • Engine Cranks But Won't Start: No fuel delivery despite the starter motor turning the engine normally.
   • Engine Stalls Unexpectedly: While driving or idling, the engine suddenly cuts out as if the ignition was turned off (often due to relay contacts opening intermittently).
   • Difficulty Starting When Engine is Hot: Heat exacerbates poor internal relay connections.
   • Intermittent Starting Problems: Starts fine sometimes, refuses others.
   • Missing "Fuel Pump Whirr" at Key On: Lack of the distinct 1-2 second priming sound from the rear when turning ignition to ON signifies a problem in the fuel pump circuit, of which the relay is a prime suspect.
   • Warning: These symptoms can also indicate a failing fuel pump, clogged fuel filter, blown fuel pump fuse, faulty fuel pump ground wire connection (especially under the driver's seat), or ignition/ECU issues. Testing the relay is an essential early diagnostic step.

6. Steps to Test the Fuel Pump Relay:

   • Safety First: Ensure the ignition key is OFF. Disconnect the NEGATIVE terminal of the battery to prevent accidental shorts or sparks.
   • Locate & Remove: Reconfirm the relay location as described earlier and carefully remove it from its socket.
   • Visual Terminal Check: Examine the relay terminals for obvious corrosion or damage. Clean gently with electrical contact cleaner and a small brass brush if necessary.
   • Testing with Multimeter (Resistance - Coil):
     • Set your multimeter to measure Ohms (resistance).
     • Identify the two smaller terminals on the relay base corresponding to the electromagnet coil (refer to a relay diagram for your specific relay type - common types like Bosch-style are standardized).
     • Touch the meter probes to these two coil terminals. A good relay coil typically shows a resistance value between 50 to 120 Ohms. An Open Circuit (OL) reading indicates a broken coil – relay is faulty.
   • Testing with Multimeter (Resistance - Contacts):
     • Identify the two larger terminals corresponding to the switched contacts.
     • Touch the meter probes to these contact terminals. An unenergized (relay "off") relay should show an OL (open) reading between the contact terminals.
     • To test contact closure:
       • Apply a small 9V or 12V DC source (like a small battery) across the two coil terminals identified earlier. This simulates the ignition signal and "energizes" the relay electromagnet inside.
       • While power is applied to the coil terminals, measure the resistance between the two larger contact terminals. A good relay should now show very low resistance (near 0 Ohms). This confirms the contacts close properly when energized.
       • If the contacts remain open (OL) when coil power is applied, the relay is faulty.
   • Basic Functional Swap Test (If Applicable):
     • If another relay in the fuse box (like the EFI Main relay or horn relay) has identical markings & pin configuration, you can swap them temporarily. Identify a relay that controls a function you can easily test safely, like the horn. If swapping the suspected fuel pump relay with a known good relay of the same type makes the horn work/stops working, and conversely might resolve the starting/stalling issue temporarily, it points strongly to the original relay being faulty.

7. Replacing the Fuel Pump Relay - Important Considerations:

   • OEM Part Number (Highly Recommended): Source the correct Toyota part if possible. Common numbers for 1980s models include 89610-12020, 85915-30030, or similar variants. Using an incorrect relay could lead to intermittent failure or potential circuit damage. A reputable auto parts store can cross-reference your old relay if OEM is unavailable, but ensure voltage rating, current rating, terminal configuration (pin layout), and physical size match exactly.
   • Purchase: Acquire the replacement relay (OEM or exact equivalent).
   • Replacement: Ensure ignition is OFF. Disconnect the battery ground cable. Carefully pull the old relay straight out. Align the new relay correctly (matching terminal orientation) and push it firmly into the socket until fully seated. Reconnect the battery terminal.
   • Test: Turn ignition Key ON and listen for the fuel pump prime. Attempt to start the engine. Confirm normal operation.

8. When Replacing the Relay Doesn't Fix the Problem:

   • Check Fuse: Verify the main EFI fuse (usually 15A or 20A, labeled on the fuse box lid) and the fuel pump fuse (often 15A). Look for any blown fuse.
   • Check Wiring: Inspect the wiring harness connector plugged into the relay socket for bent pins, corrosion, or looseness. Trace the wire bundle leading from this connector for signs of damage or chafing, especially where it routes near sharp brackets through the firewall.
   • Fuel Pump Check: If the relay tests good and swaps successfully, but no prime sound or fuel pressure exists with Key ON, the fuel pump or its circuit wiring becomes the primary suspect.
   • Ground Connection: The fuel pump relies on a critical ground wire connection. On 1980s Toyotas, this is often located underneath the driver's seat area, bolted to the body. Common failure point: disconnect, clean the ring terminal and attachment point thoroughly with sandpaper or a wire brush, reattach securely. Corrosion here mimics a failed relay or pump.
   • Ignition Switch: Faulty ignition contacts can fail to send the 'Key ON' signal energizing the relay coil.
   • ECU Issues: Though less common on these simpler trucks, a problem with the engine computer (ECU) could theoretically prevent the signal to energize the relay coil.

Key Takeaway: Knowing the precise 1986 Toyota Pickup Fuel Pump Relay Location inside the driver's side engine fuse/relay box is step one in diagnosing frustrating non-start or stalling issues. While its job is critical, accessing and testing it is a straightforward task for most owners equipped with basic tools. Always prioritize safety (battery disconnect), methodically identify the component using labels and terminal positions, and use simple multimeter tests or symptom checks to verify its function before proceeding with potentially more invasive fuel pump diagnostics. Replacing this relatively inexpensive relay is often the solution to restoring reliable operation.