Could Your Fuel Issue Be Due to a Bad Relay?

Posted on: 25 September 2019

If you have been turning over your car's ignition for some time and you're getting nowhere, you may suspect that you have a fuel delivery problem. After all, the battery has got plenty of "juice" and the starter motor also appears to be fine. In this case, you may suspect that you have a faulty fuel pump, but it could be something as relatively simple as a relay. If you don't know much about these electrical components, how should you proceed?

Switching Action

Most major electrical components on a car or truck are activated through a relay which is, for all intents and purposes, an on or off switch. Manufacturers add these relays to a typical car configuration as it allows them to use a much smaller and safer current for most of the vehicle and they can use cheaper gauge wire for the primary circuit.


It may be possible for you to test the functionality of this relay, but you will first need to locate it. It could be in a number of different places and it's best to refer to the vehicle handbook first to save a lot of time.

Straight Swap

As you look through the vehicle manual, see if there are any other relays of similar size or configuration that are situated close to the fuel pump relay. If so, and the other relay has the same number and arrangement of terminals, you can simply swap over the leads and see if that does the job.


Have a closer look at the fuel pump relay to see if it is sitting correctly in its receptacle and is still connected properly. Sometimes, the relay may vibrate and work itself loose and you may simply need to reconnect it. If you can see any corrosion, then you should try and clean the terminals carefully before you attempt to restart the engine.


Alternatively, you can conduct a test using a simple tool or a digital multimeter. You can connect these tools to the relevant terminals (as specifically identified by the owner's manual) to see whether you have any continuity between the circuit terminals. If you do not, you will have to replace the relay. Make sure that you get one that is of the same configuration.

Bringing in the Experts

If all seems to be good with the relay, then you may have a problem elsewhere within the system, or the fuel pump might be bad after all. Replacement is quite an involved job and is best left to the professionals, so you should take the vehicle in for a service as soon as possible.

For help with this or other issues, contact an auto electrician in your area.