Welcome to my blog. My name is Ken. One day, I was driving home from work when the engine in my car failed. While I waited for the recovery truck to arrive, I realised I didn’t have a clue what went on underneath the bonnet of my car. I signed up for an auto service course at my local community college, so I could gain the skills I needed to properly maintain my car and repair it if something when wrong while I was on the road. I wanted to start a blog to pass on these skills to other people so that they can look after their automobiles.
If you cannot start your car or truck in the morning and the symptoms are similar to a lack of fuel, you may suspect a faulty pump. Yet before you assign blame and think about replacing this component, you may need to take one step back and look at your auto electrics instead. Did you know that there is an additional stage in between your ignition switch and the pump itself? Could the fault lie here?
Different Circuitry
The typical vehicle today has metres upon metres of electrical cable designed to connect control points to the components themselves. These cables are set out in two individual circuits, with some of them low-powered and others receiving a far higher current. It can be safer and less expensive to use a thinner gauge wire and low current circuits where needed and to add the second gauge wire sparingly.
So, there are two different circuits in between your ignition switch and the fuel pump, made up of low and high current feeds. However, in between those two circuits, there is a separate component known as a relay.
What Is A Relay?
The relay is, to all intents and purposes, a glorified switch. It contains an electromagnetic coil that closes a pair of metal contacts to activate the larger circuit when it receives a signal from the ignition switch. This will then send the necessary power to the fuel pump so that it can kick into life and deliver your petrol.
Checking The Relay
If the relay in question is not working for any reason, the fuel pump will not work. You will need to check the relay first before blaming the pump, and it is possible to do this with a relay tester. If you have one of these (or a digital multimeter) in your garage, you can follow the specific manufacturer instructions to test the relay. You'll usually have to connect the terminals to the relay pins to get a reading. Relays are found underneath the bonnet and in the same general area as the fuse box, and a simple diagram on the lid should indicate which relay to test.
Over To The Experts
Of course, if you don't have those gadgets or are unsure how to proceed, it's a job for a mechanic. They'll certainly test the relay and all the rest of the wiring, and if everything is in order, they will also troubleshoot the pump.
Share12 April 2022
