How to check the relay in the car?

If you don't deal with cars professionally, you may not even be aware of the existence of automotive relays. And they are also the element that links the various systems in the car and makes everything work really efficiently. Therefore, you need to know how to check the relay. It really isn't difficult! However, you should always start from scratch. You should know how to check the health of the relay, but not only. In our article, we will first explain how this element works and what function it performs in a car. We'll also describe the most common symptoms of a bad relay so you can figure out if it's not working as it should. Find out more about this little device that plays an important role in your car!

How does an automotive relay work?

At the very beginning, it is necessary to explain how an automotive relay works. This is a small electrical device. Power is supplied through its coil. Thus, the contacts that send the signal are switched. It is the relay that can, for example, turn on the turn signal when the corresponding button is pressed. Current can be transported from the battery and used to power various vehicle functions. Before we move on to testing the relay, it is worth learning about the types of devices that transmit voltage.

Popular types of automotive relays

Automotive relays can be of different versions. However, these devices can be divided into two large groups. The first are those relays that increase the voltage above 14,5 W, and the second are those that reduce it. The first type is always associated with a brush node. It is connected to a generator. Relays can also be divided, for example, into Canadian, French and others, which differ from each other in the way they are connected.

Damaged starter relay - you will quickly recognize the symptoms

How to check the relay? At the very beginning, in order for it to make sense at all, you need to pay attention to the symptoms that will appear in the car. If the starter relay has failed, you will have trouble starting the car. The device will not send out a strong enough signal, so the vehicle will not be able to move. You may also find that the starter does not disengage after it starts to supply current. Also note if the starter seems to be erratic and sometimes starts the engine and sometimes doesn't. Problems should also be signaled by a ticking sound.

How to check the fuel pump relay - symptoms

The symptoms of a faulty automotive fuel pump relay can be similar to those of a starter problem. In this situation, fuel will not enter the vehicle in the correct amount, so the vehicle may not start. So, if you notice that the engine is running fine, but the car still won't start, check the fuel pump relay. Then we can assume that the car "scrolls, but does not start." Often such a problem is immediately diagnosed as a fuel pump failure, but this will not always be the correct diagnosis.

How to test the glow plug relay?

Glow plugs also have their own relay. If they are not powered or connected properly, they may simply not work at all. How to test the glow plug relay? You may notice something is wrong when:

• an error code will be generated;
• after starting the car starts to smoke and runs very unevenly;
• the control lamp does not light up or burns too long.

How to check the relay and where to look for it?

First of all, if your machine is running fine, you probably don't need to worry about the relay. However, if your car is going to the mechanic anyway, you can ask them to do an additional check. How to check if the relay is working? The easiest way to check those elements that have a transparent body. You will clearly see if something accidentally burned out, and this may be a signal that something is wrong. You will find the relay in the fuse box.

How to effectively test an automotive relay?

How to check the relay? Be sure to start by checking the performance of all wires. Make sure they haven't been burned or torn out in any way. If your car is parked on the street or in a leaky garage at night, some animal may have chewed through the cables. Also check the input voltage and grounding with a fuse. However, you must remember that the layouts may differ depending on who produced them. First, find out exactly what type you are dealing with to make it easier for you. That way you won't damage anything.

How to check the relay outside the car?

You can check the operation of the relay outside the car. However, for this you will need specialized equipment:

• to measure;
• wires;
• amplifier. 

The last element can be made, for example, from an old computer power supply. Set the meter to test the diode, then connect it properly. In just a dozen or so seconds, you will be able to check if the meter is showing power.

How much does it cost to replace a relay?

Since you already know how to test an automotive relay, you are probably wondering how much it can cost to replace such an item. Luckily, you won't pay too much. Of course, prices will vary depending on the year of the car, its model, manufacturer, etc., but usually around 15 euros is enough, this is not a big expense, so the relay should be checked first. Because if you decide that the problem is something else and try to replace a working fuel pump, you will spend much more on it.

Knowing how to test an automotive relay is undoubtedly useful. Some people confuse the symptoms of this item with a bad fuel pump and replace it. This, of course, generates unnecessary costs. If you know how to test a relay, you will definitely avoid such mistakes.