1999 Toyota Tacoma Fuel Pump Fuse Location: A Complete Guide to Finding and Fixing It

If your 1999 Toyota Tacoma cranks but won't start, the very first thing you should check is the fuel pump fuse and relay. On a 1999 Toyota Tacoma, the fuel pump fuse and relay are located in the under-hood fuse box, which is also called the junction block or power distribution center. This black plastic box is positioned on the driver's side of the engine compartment, right behind the battery. The fuel pump relay is labeled as the "EFI" (Electronic Fuel Injection) relay, and the fuse is a 15-amp fuse also labeled "EFI." If you have a no-start condition, checking these two components first can save you hours of unnecessary work and hundreds of dollars in parts.

Understanding the Fuel Pump Fuse and Relay

Before you start digging into your truck, it helps to understand what these two parts do. The fuel pump relay acts as an electrical switch. When you turn the key to the "on" position, the engine control unit (ECU) sends a small signal to the relay. The relay then closes, allowing a much larger current to flow from the battery to the fuel pump. This design keeps heavy wiring away from the dashboard and ignition switch. The fuse is a safety device. It is a weak link in the circuit designed to blow if the fuel pump draws too much current due to a short circuit or a failing pump. When the fuse blows, it cuts power to the pump and prevents damage to the wiring or even a fire.

Why You Should Check the Fuse and Relay First

A failed fuel pump relay or a blown fuse is one of the most common causes of a no-start condition on a 1999 Toyota Tacoma. Both are inexpensive and easy to test, making them logical starting points. If your engine cranks but refuses to start, or if it stalls unexpectedly, a blown fuel pump fuse or a faulty relay is one of the first things to check. The cost of a new relay or fuse is under $20, and testing them takes about 10 minutes. Replacing a fuel pump, on the other hand, can cost $300 to $600 and takes several hours of work. Checking the electrical side first is just smart troubleshooting.

Step-by-Step Guide to Locate the Fuel Pump Fuse and Relay

Step 1: Open the Hood and Find the Fuse Box

Open the hood of your 1999 Toyota Tacoma. Look for a rectangular black plastic box on the driver's side, near the battery. This is the under-hood junction block, also called the engine compartment fuse box. It is usually located behind the battery, closer to the firewall. The box has a plastic lid that you can remove by pressing the clips on the sides.

Step 2: Remove the Lid and Check the Diagram

Remove the plastic lid from the junction block. Look at the diagram printed on the underside of the lid. This diagram shows the location of every fuse and relay inside the box. You are looking for labels such as "EFI" (Electronic Fuel Injection) or "FP" (Fuel Pump). On the 1999 Toyota Tacoma, the fuel pump relay is labeled as the "EFI" relay. The fuse is also labeled "EFI" and is a 15-amp fuse.

Step 3: Identify the Correct Fuse and Relay

The 15-amp EFI fuse is typically located in the main fuse box under the hood. The EFI relay (fuel pump relay) is also inside this same box. On the 1999-2001 Tacoma, the EFI relay is usually on the far-right side of the junction block, and it is the second relay from the bottom. The relay itself is a small, square or rectangular black plastic component with four or five pins on the bottom.

Step 4: A Note on the Circuit Opening Relay

On the 1997 and 1998 Tacoma models, there is an additional component called the "Circuit Opening Relay." This relay is located under the dashboard, often above the steering shaft or near the steering column. The circuit opening relay is another safety device that must be activated for the fuel pump to run. If you have a 1999 Tacoma, this relay may still be present, but the primary fuel pump relay is the EFI relay in the under-hood fuse box. If you have checked the EFI relay and fuse and the pump still won't run, the circuit opening relay under the dash is your next stop.

How to Test the Fuel Pump Fuse

Testing the fuse is the easiest part of the job. Here is how to do it safely.

Step 1: Remove the Fuse

With the ignition off, locate the 15-amp EFI fuse in the under-hood fuse box. Use a fuse puller (usually clipped to the inside of the fuse box lid) or a pair of needle-nose pliers to gently pull the fuse straight out.

Step 2: Visual Inspection

Hold the fuse up to the light. Look through the clear plastic body at the metal strip inside. If the metal strip is broken, melted, or separated, the fuse is blown. A blown fuse is obvious and will show a clear break in the metal.

Step 3: Use a Multimeter (Optional but Recommended)

If the fuse looks good visually, it may still be damaged internally. Use a multimeter to test for continuity. Set the multimeter to the continuity or resistance setting. Touch one probe to each of the two metal prongs on top of the fuse. If the multimeter beeps or shows a reading of near zero ohms, the fuse is good. If it shows no continuity, the fuse is blown.

Step 4: Replace the Fuse

If the fuse is blown, replace it with a new 15-amp fuse of the same rating. Never use a higher amperage fuse, as this can lead to fire hazards or damage to the wiring harness. If the new fuse blows immediately, this indicates a short circuit in the wiring, which requires further investigation.

How to Test the Fuel Pump Relay (EFI Relay)

Testing the relay is a little more involved but still straightforward. Here are a few methods.

Method 1: The Swap Test

This is the easiest method. Identify a relay in the same fuse box that is identical to the EFI relay. Common candidates include the horn relay, the headlight relay, or the cooling fan relay. Remove the EFI relay and swap it with one of these identical relays. If the fuel pump starts working after the swap, the original EFI relay is faulty. If the part you swapped also fails, you may have a wiring issue.

Method 2: The Listen Test

Have a helper sit in the driver's seat. Turn the ignition key to the "on" position (do not crank the engine). Listen carefully for a brief humming or buzzing sound from the rear of the truck, where the fuel tank is located. This is the sound of the fuel pump priming. If you hear nothing, the relay or fuse may be the problem. You can also place your fingers gently on the EFI relay while your helper turns the key. You should feel and hear a distinct, soft "click" as the relay energizes. If you hear no click, the relay is likely not receiving power.

Method 3: Use a Multimeter

With the relay removed, you can test it with a multimeter. A standard automotive relay has four or five pins labeled 30, 85, 86, and 87 (and sometimes 87a). Set the multimeter to continuity mode. Check for continuity between pins 85 and 86. You should see continuity (the coil is good). Next, check for continuity between pins 30 and 87. You should see no continuity (the switch is open). Now, apply 12V power to pins 85 and 86 (using a battery or a power supply). You should hear a click, and now there should be continuity between pins 30 and 87. If the relay fails any of these tests, replace it.

What to Do If the Fuse and Relay Are Good

If you have tested the EFI fuse and the EFI relay and both are good, the problem lies elsewhere. Here are the next steps to check.

Check the Fuel Pump Itself

The fuel pump may have failed. You can test for power at the fuel pump connector. On the 1999 Toyota Tacoma, the fuel pump is located inside the fuel tank. You can access the electrical connector under the rear seat or by dropping the fuel tank. Use a multimeter to check for 12V power at the connector when the key is turned to the "on" position. If you have power and ground, but the pump does not run, the pump is likely bad.

Check the Wiring and Connectors

Corrosion, loose connections, or damaged wiring can prevent power from reaching the fuel pump. Check the wiring harness between the fuse box and the fuel pump. Look for frayed wires, melted insulation, or corroded connectors. A good spot to test is the connector under the left seat. This checks that everything on the cab side is working correctly.

Check the Circuit Opening Relay

As mentioned earlier, the 1999 Tacoma may have a circuit opening relay under the dashboard. This relay is controlled by the ECU and must be activated for the fuel pump to run. If the EFI relay and fuse are good, but the pump still won't run, check the circuit opening relay. It is usually located above the steering shaft on the driver's side.

Symptoms of a Faulty Fuel Pump Relay

Knowing the symptoms of a bad fuel pump relay can help you narrow down the problem without even lifting the hood. Common symptoms include:

  • Engine cranks but does not start. This is the most classic sign. The starter motor turns the engine over, but the engine never fires because no fuel is being delivered.
  • No sound from the fuel pump. When you turn the key to the "on" position, you should hear a brief humming sound from the fuel tank. If you hear nothing, the relay or fuse is likely the issue.
  • Sudden stalling while driving. A failing relay can cause the fuel pump to lose power intermittently, causing the engine to stall without warning.
  • Intermittent starting issues. The truck may start fine one day and refuse to start the next. This is a common sign of a relay that is failing due to heat or age.

Safety Precautions

Working on your vehicle's fuel system requires caution. Always follow these safety rules:

  • Disconnect the battery. Before working on any electrical components, disconnect the negative terminal of the battery to prevent accidental shorts or sparks.
  • Work in a well-ventilated area. Fuel vapors are flammable. Work outdoors or in a garage with the doors open.
  • Avoid open flames. Do not smoke or use any open flame near the vehicle while working on the fuel system.
  • Use insulated tools. This reduces the risk of electrical shorts.
  • Relieve fuel system pressure. Before disconnecting any fuel lines, remove the fuel pump fuse and run the engine until it stalls. This relieves pressure in the fuel lines.

Tools You Will Need

Here is a list of tools that will make the job easier:

  • Owner's manual or fuse box diagram. This is your best guide for finding the exact location of the fuse and relay.
  • Multimeter. Essential for testing continuity and voltage.
  • Fuse puller. Usually included in the fuse box, but needle-nose pliers work too.
  • Screwdriver. For removing panels or clips on the fuse box.
  • Flashlight. The fuse box can be in a dark area, so a flashlight is helpful.
  • Spare 15-amp fuse. Always keep a few spare fuses in your glove box.
  • Replacement relay. If you suspect the relay is bad, you can buy a replacement at any auto parts store. The Toyota part number for the EFI relay is 85910-04010.

Why This Matters for Your 1999 Toyota Tacoma

The 1999 Toyota Tacoma is a reliable truck, but it is now over 25 years old. Electrical components like relays and fuses can fail over time due to heat, vibration, and corrosion. Knowing where the fuel pump fuse and relay are located and how to test them is a valuable skill for any Tacoma owner. It can save you from being stranded on the side of the road or from paying a mechanic hundreds of dollars for a simple fix.

The Most Common Mistakes DIYers Make

When troubleshooting a no-start condition, many people make the mistake of immediately assuming the fuel pump is bad. They drop the fuel tank, replace the pump, and still have the same problem. The real issue is often a $10 relay or a $0.50 fuse. Always start with the simplest and cheapest checks first. Another common mistake is using a fuse with the wrong amperage. If you install a 20-amp fuse where a 15-amp fuse is required, you risk damaging the wiring or causing a fire.

When to Call a Professional

If you have checked the EFI fuse, the EFI relay, the circuit opening relay, and the wiring, and the fuel pump still does not run, it may be time to call a professional mechanic. There could be a problem with the ECU, the fuel pump itself, or a more complex wiring issue. A qualified mechanic with a diagnostic scanner can read fault codes from the ECU and pinpoint the problem more quickly.

Summary

The 1999 Toyota Tacoma fuel pump fuse and relay are located in the under-hood fuse box on the driver's side, behind the battery. The relay is labeled "EFI" and the fuse is a 15-amp fuse also labeled "EFI." Testing these two components is the first and most important step when diagnosing a no-start condition. A blown fuse or a faulty relay is a cheap and easy fix. If both are good, move on to checking the circuit opening relay under the dash, the wiring, and finally the fuel pump itself. By following this systematic approach, you can save time, money, and frustration.

Upgrade Your Tacoma with a High-Performance KEMSO Fuel Pump

If your 1999 Toyota Tacoma's fuel pump has failed, or if you simply want a reliable upgrade, consider a KEMSO fuel pump. KEMSO offers high-performance fuel pumps that are designed as direct OEM replacements. Their pumps are engineered to deliver superior flow and pressure compared to stock units, making them ideal for daily drivers, work trucks, or even performance builds. Each KEMSO pump is a high-pressure unit capable of supporting applications up to around 700-800 horsepower, yet it fits perfectly as a direct replacement for your original factory pump.

The KEMSO 340 pump, for example, is similar to the popular Walbro 255 but offers more flow. It delivers 340 liters per hour at 43 psi, ensuring your engine gets all the fuel it needs, even under heavy load. The kit comes complete with everything you need for installation, including fuel strainers, hoses, wiring connectors, and clamps. One of the best reasons to choose KEMSO is their lifetime warranty. If your KEMSO pump ever fails due to a manufacturing defect, you get a replacement at no cost. This kind of confidence is rare in the automotive parts industry and gives you total peace of mind.

Visit KEMSO Racing today to find the perfect fuel pump for your 1999 Toyota Tacoma. Browse their full catalog of high-performance fuel pumps for cars, trucks, motorcycles, and more. All pumps are backed by a lifetime warranty, free shipping, and easy returns. Whether you need a stock replacement or an upgrade, KEMSO has you covered at a price that is often less than half the cost of dealer parts.

Check out the full selection at: https://www.kemsoracing.com/


Back to blog