2005 Toyota Tacoma Fuel Pump Relay Location: Quick Guide to Finding It and Fixing the No-Start Problem

The bottom line: The fuel pump relay on a 2005 Toyota Tacoma is located inside the engine compartment fuse box, which sits on the driver's side near the battery. If your Tacoma cranks but won't start, a faulty fuel pump relay is a common culprit. This guide walks you through locating the relay, testing it, and getting your truck back on the road.

The 2005 Toyota Tacoma, including the X-Runner and PreRunner trims, relies on a fuel pump relay to send power from the battery to the fuel pump inside the gas tank. When you turn the key to the "ON" position, this relay clicks shut and powers the pump for a couple of seconds to prime the fuel system. If the relay fails, the pump gets no power, and the engine won't start even though the starter motor turns fine. This is a straightforward DIY fix that can save you a trip to the mechanic, and in most cases, the solution is simply replacing a $20 relay.

Where Exactly Is the Fuel Pump Relay Located?

On the 2005 Tacoma, the fuel pump relay lives in the under-hood fuse and relay box. This black plastic box is positioned on the driver's side of the engine bay, near the battery and firewall . It's the same box that holds fuses for the EFI system, headlights, and other critical electronics.

Here's how to find it in under two minutes:

  1. Open the hood and secure it with the prop rod. Look toward the driver's side corner, right behind the headlight and next to the battery. You'll see a rectangular black box with a removable lid .
  2. Remove the fuse box cover. Press the tabs on the sides or lift the latch, then flip the lid over. The underside of the lid has a diagram that labels every fuse and relay, including the fuel pump relay .
  3. Identify the relay. On the diagram, look for a label that reads "EFI" (Electronic Fuel Injection) or "Fuel Pump" . On many 2005 Tacoma models, this relay is labeled "EFI" and handles both the fuel injection system and the fuel pump .
  4. Visually confirm. Once you've located the spot, pull the relay straight out. It's a small, cube-shaped component with four or five metal prongs on the bottom. The relay's plastic housing will typically have a small diagram printed on it showing the terminal numbers .

A quick note on variations: While the under-hood fuse box is the standard location for all 2005 Tacoma trims (Base, PreRunner, X-Runner, 2WD, and 4WD), the exact relay position within the box might differ slightly based on whether your truck has optional features like daytime running lights. Always rely on the diagram on the fuse box lid first .

Symptoms of a Bad Fuel Pump Relay

Before you start replacing parts, it helps to know what a failing relay actually feels like. The most common symptoms include:

  1. Engine Cranks But Won't Start: This is the classic sign. You turn the key, the starter motor spins the engine, but it never fires up. You also won't hear the fuel pump's quiet whirring sound from the rear of the truck when you first turn the key to "ON" .
  2. Intermittent Stalling: The relay may work sporadically, causing the engine to die suddenly while driving and then restart after a few minutes when the relay cools down or re-seats itself .
  3. No Fuel Pump Prime Noise: When you turn the ignition to the "ON" position (without cranking), you should hear a faint buzzing or humming from the fuel tank area for 1-2 seconds. If there's total silence, the relay may not be sending power .
  4. Check Engine Light: In some cases, a failing relay will trigger a diagnostic trouble code related to fuel pressure or a lean condition, illuminating the check engine light.

How to Test the Fuel Pump Relay

You don't need to be an electrician to test this relay. A simple swap test is the easiest method. Here are two ways to do it:

Method 1: The Swap Test (Easiest)

  1. Find the fuel pump relay and pull it out of the fuse box .
  2. Look for a relay with the identical part number or the same terminal layout. On the 2005 Tacoma, the HORN relay or the HEAD (headlight) relay are often compatible .
  3. Swap the relay from the known-working circuit (like the horn) into the fuel pump socket.
  4. Turn the key to "ON" and listen for the fuel pump prime. Turn the key further to crank the engine. If it starts, your relay was bad. If it doesn't, the problem is elsewhere (fuel pump, wiring, or the ECM).

Method 2: The Bypass Test (More Direct)

This method directly powers the fuel pump to confirm the pump itself is good .

  1. Pull the fuel pump relay out of the box.
  2. Look at the relay socket. You'll see four terminals. The two larger ones are typically Terminal 30 (power input) and Terminal 87 (power output to the fuel pump) . The two smaller ones are Terminal 85 and 86 (coil terminals) .
  3. Take a short piece of wire (a paperclip works) and connect Terminal 30 and Terminal 87 in the socket .
  4. Turn the ignition key to "ON" (do not start the engine). If you hear the fuel pump humming from the tank, the pump is functional, and the relay is the issue. Important: Remove the jumper wire immediately after testing. Never drive with the jumper in place .

Step-by-Step: Replacing the Fuel Pump Relay

Once you've confirmed the relay is bad, replacement takes about five minutes.

  1. Purchase the correct relay. You can buy an OEM Toyota relay or a compatible aftermarket one from any auto parts store. Bring your old relay to the store to match it perfectly .
  2. Disconnect the battery negative terminal. This is a safety precaution to prevent any electrical shorts while you're working in the fuse box.
  3. Remove the old relay. With the fuse box lid off, firmly grip the relay between your thumb and forefinger and pull it straight up. It might require a slight wiggle, but it should come out without much force.
  4. Install the new relay. Align the prongs with the socket in the fuse box. Push the relay straight down until it clicks securely into place.
  5. Reconnect the battery and test. Turn the key to "ON" and listen for the fuel pump. Then, start the engine. If it fires up and idles smoothly, the job is done.

What If the Relay Is Fine? Check the Fuel Pump Shut Off System

If you've replaced the relay and your Tacoma still won't start, don't panic. There's a safety feature you should check before diving into a fuel pump replacement. The 2005 Tacoma is equipped with a fuel pump shut off system. This system stops the fuel pump automatically if the engine stalls or if an airbag deploys in a collision, to minimize the risk of a fuel leak .

If this system has been triggered (even by a very hard bump or an accidental activation), the fuel pump won't run. Here's how to reset it :

  1. Turn the engine switch to the "ACC" or "LOCK" position.
  2. Wait a few seconds.
  3. Turn the key to the "ON" position and try to start the engine as you normally would.

Just remember to check the ground for any fuel leaks before you attempt to restart. If fuel is leaking, do not start the engine—the fuel system is damaged and needs professional repair .

Is It the Relay or the Fuel Pump?

If the relay tests fine and the shut-off system is reset, the issue likely lies with the fuel pump itself. Here's a quick way to differentiate:

  1. Listen for the pump: Turn the key to "ON" (without cranking). Listen near the fuel tank. If you hear a whine or buzz, the pump is running. If you hear nothing, the pump may be dead .
  2. Check the wiring: On a 2005 Tacoma, the wire that powers the fuel pump from the relay is often Pink or Red . Some owners have found that a previous owner or a repair shop cut splicing wires under the fuse box caused poor connections. Trace the wire from the relay socket back a few inches to see if a connection looks corroded or has come loose .
  3. Fuel pump replacement: If you determine the pump itself is faulty, expect to pay between $400 and $800 for a professional replacement, including parts and labor. The cost varies based on whether you use an OEM or aftermarket pump and the shop's labor rate . The fuel pump is located inside the fuel tank, so the mechanic will need to either drop the tank or use an access panel to replace it .

For a 2.7L four-cylinder or 4.0L V6 engine, checking the relay is always the first, cheapest diagnostic step. Replacing a faulty relay is a $20 fix and a five-minute job, which is far better than paying for a $600 fuel pump installation.

Choose a Reliable Fuel Pump from KEMSO

If you've tested everything and need a replacement fuel pump for your Tacoma or any other vehicle, consider KEMSO. KEMSO fuel pumps are known for their high performance and durability. Each pump is built as an OEM replacement, meaning it's designed to meet or exceed the original factory specifications for fit, form, and function. Whether you drive a Toyota pickup, a Subaru Impreza, or a BMW motorcycle, KEMSO has a fuel pump that will keep your engine running smoothly. Plus, every KEMSO fuel pump comes with a lifetime warranty, giving you peace of mind long after the installation is done. Visit https://www.kemsoracing.com/ to browse their full line of fuel pumps and find the right one for your vehicle.

In summary: Locating and replacing the fuel pump relay on your 2005 Toyota Tacoma is one of the easiest and most cost-effective engine diagnostics you can do. The relay is in the under-hood fuse box on the driver's side. Test it with a simple swap, replace it if needed, and check the fuel pump shut-off reset before moving on to more expensive repairs. If the pump itself needs replacing, trust a quality brand like KEMSO for a reliable fix. For all your fuel pump needs, check out https://www.kemsoracing.com/.


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