Fuel Pump Relay Symptoms:Troubleshooting & Repair Guide For Beginners

Naomi O'Colman

Fuel Pump Relay Symptoms

Fuel Pump Relay Symptoms

If your car won’t start, the fuel pump often gets blamed. So, what are a fuel pump relay and its symptoms? Let’s get a better insight into this issue.

What Is Fuel Pump Relay?

A fuel pump relay (or electrically operated magnetic clutch) helps divert power to the starter motor when the engine loses prime. When your car’s battery dies, you get no power for your ignition switch. To turn the key on and off, you’ll need an electrical device like a relay or solenoid that can simulate this function of an ignition switch.

Relays are the way to go because they are fast easy to install and much cheaper than a solenoid.

The fuel pump relay is placed at the rear of the engine. It has two terminals that connect to two wires that go back into the ignition switch under the hood. The wire you will have to test for are usually numbers 7 and 9. These can be found under the dash on either side of your steering column (if you drive a car with an automatic transmission).

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What Causes a Fuel Pump Relay to Fail?

Damage Caused by Water

If your fuel pump relay has been damaged by water, you will first notice that the interior of your vehicle is wet. This will happen during or after a rainstorm. Sometimes, you may notice that rusting is the cause of the failure. Then again, it could also be corrosion from acid rain. The bottom line is moisture has entered the relay, causing it to fail prematurely.

More common causes are corrosion at the terminals. Another problem is caused by water leaking near the relay. Oxidation of the connectors also causes them to fail prematurely.

Faulty Connections

If you have any electrical problems in your vehicle, be sure to check your fuel pump relay. The connection between these two parts can be faulty, causing them to become damaged over time. Replacing this part will keep it working properly and keep your car running correctly.

Discolored and/or Cracked Contacts

You need to clean the connections behind the dash. If you don’t, they will fail prematurely. When this happens, your car will suddenly shut off without warning. If you do not notice this soon enough, it could cause permanent damage to the relay or ignition switch. This could also lead to more serious damage if not fixed right away.

What Symptoms Does a Fuel Pump Relay Present?

#1 Loss of power

A fuel pump relay protects your car’s electrical components. If it fails, one of your car’s functions will cease working. This is most likely the problem with your car running unexpectedly, giving you no warning that it is about to die. You will have no power for the ignition switch until you open the door and manually turn your car on. To do this, all you need to do is turn the key on and off again.

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#2 Engine Stalling

If you have a fuel pump relay, and it fails, there is a chance that your car will stall. This will happen in the middle of the road. Once this happens, you will need to check under the hood for any leaks or bad connections. Then again, it could be due to your fuel pump if you just purchased a used vehicle.

#3 Difficulty Starting

If you have a faulty fuel pump relay, there is a chance that your engine will have difficulty starting. This is because the relay protects your fuel pump from being damaged from power surges. One telltale sign of a bad fuel pump relay is when you turn the ignition switch to start the engine, and it doesn’t turn over right away.

#4 The Check Engine Light Will Come On/ Blinking

Another sign that your car’s fuel pump relay is about to fail is if your check engine light comes on. This light is often referred to as the MIL light, or the illuminated check engine. This means that there is a problem with your car’s fuel system. The check engine light will turn on when the relay fails, making it difficult to start or drive your car normally.

Another sign that your fuel pump relay is about to fail is if your check engine light blinks, this indicates an issue with your ignition system.

#5 No Noise from Fuel Pump

If you have a fuel pump relay, and it fails, is most likely because your fuel pump will stop working. The reason for this is that the relay protects the fuel pump from being damaged from power surges or electrical failure. In other words, if you do not have a fuel pump relay, the fuel pump would be exposed to these dangers. This would cause it to fail with no warning.

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What Is the Solution?

If your car is not starting, it’s vital that you first find out if your problem lies on the fuel pump relay or not. If this is the case, then replace it immediately. You can do this by opening up the hood and removing the steering wheel (and windshield wiper motor if applicable). Then, you will need to check your car’s wiring connections.

If you notice any discoloration of your car’s wiring, be sure to clean it with a wire brush. If the area is very dirty, you can clean it with a wire brush and a can of brake cleaner. This will remove any oxidation from the connections. If the connections are still rusty after cleaning them, then you will need to replace them before installing a new fuel pump relay.


If your fuel pump relay fails, you will not be able to start your car. This is because the relay protects the ignition switch from electrical surges. If you don’t have a fuel pump relay, then the fuel pump would be susceptible to these dangers and could fail with no warning.

This means that your car could die in the middle of nowhere and leave you stranded. On top of this, if it is in an older vehicle, it will require a replacement fuel pump relay to work again.