How To Test A Car Radiator Fan Relay

How To Test A Car Radiator Fan Relay

The failure of a cooling fan can result in poor air conditioning or engine overheating. The underlying cause is often a bad car radiator fan relay.

How To Test a Car Radiator Fan Relay Guide

There are various ways you can use to know if the radiator fan relay is working. This post will look into how to test a car radiator fan relay using simple methods.

How To Test If Your Car Radiator Fan Relay Is Working Properly

Failure of a car cooling fan system can cause the car engine to overheat, damaging a car.

Is the engine of your car overheating? Is the car’s engine cooling fan work?

The car radiator fan relay can also cause the problem. It is an essential part of a car’s cooling system.

There are ways to test your radiator fan relay to determine if it’s causing your radiator fan not to work. This guide aims to provide various ways to test a car radiator fan relay.

Each of these methods can be used by anyone, including those without motor vehicle mechanics experience.

Let’s dive into the methods and find out how you can test a car radiator fan relay.

Testing The Car Radiator Fan Relay Using A Relay Tester

If you don’t have a car radiator fan relay replacement that works, you can also use a relay tester. If swapping the relay does not identify the problem, you can also use relay testing.

Before proceeding, it is vital to ensure that the relay being tested is getting power from the computer. The best thing about using a relay tester is that it can also troubleshoot all car relays.

The only thing you need to do is follow the instructions provided on the tool.

Testing A Car Radiator Fan Relay Using A Digital Multimeter

A digital multimeter is another alternative if you don’t have the budget to purchase a relay tester. It is very handy for many vehicle and home electronics troubleshooting tasks.

Using a multimeter is another way of testing if the car radiator fan relay is working.

You can find a multimeter from a local hardware store, a department store, an electronics store, or an online store.

Testing A Car Radiator Fan Relay Using A Digital Multimeter

  1. First, you need to remove the car radiator fan relay from the fuse box.
  2. Check the car radiator fan relay to ensure that it does not have any damaged terminals or wires.
  3. Identify the terminals and pins on the relay that are part of the control and power circuits.
  4. Identify the car radiator fan relay terminals, then set the digital multimeter to continuity.
  5. Visually inspect the car radiator fan relay for any sign of corrosion. Corrosion of the car radiator fan relay can prevent the normal flow of current the rough the relay. If the relay shows signs of corrosion, clean the terminals and socket using an electrical contact cleaner.
  6. Check the car radiator fan relay for signs of overheating. Overheating is a sign of a problem within the car radiator fan relay or circuit that the relay is connected to.
  7. Before you start to test the relay, make sure that you set the multimeter to measure DC voltage.
  8. With the switch in the car activated, test resistance between the relay’s poles and pole’s corresponding NO and NC contacts. The NC and NO contacts reading should be 0 ohms and infinite resistance to the corresponding pole, respectively.
  9. Connect one lead of the digital multimeter to the power terminal and the other lead to the power terminal.
  10. If the multimeter displays a zero, the power pins of your car relay are not working. Therefore, you should replace it with a new one that is working.
  11. Check for bad and disconnected wires, corroded connections and terminals, and short circuits if the relays are working.

How To Test a Car Radiator Fan Relay

Other Ways To Test If A Car Radiator Fan Relay Is Working

Listening For Component Noises In The Fan Relay

Another way to test a car radiator fan relay is shaking the fan relay and listening for any noises inside.

If you hear a rattling sound in the relay, chances are it is broken and needs to be replaced immediately.

Bumping Or Thumping The Car Radiator Fan Relay

You can test your fan relay to check if it is good is thumping and checking if it clicks on. When testing, listen to the fan relay and see if it clicks when powered.

However, clicking does not mean that the car radiator fan relay is good. The relay can click but still fail to power the cooling fan.

Swapping The Car Radiator Fan Relay

Many cars use one fan for the A/C condenser and radiator. Some use a different relay for the condenser.

As such, engine overheating can be caused by the common relay. The easiest method to test if your car radiator fan relay is working is to swap it with another one.

Switching on the air conditioning can tell you if the car radiator fan relay is to blame for overheating. If the fan fails to engage, the problem could be the fan relay.

You can test it by swapping the car radiator fan relay with a different one that you are sure works. Several relays in a car are almost similar to one another.

You can acquire a new relay from your nearest authorized automobile spare parts dealer store.

Alternatively, you can also get a similar relay by looking at the power center found under the hood.

Make sure that you use a relay that will not interfere with the normal functioning of the engine when swapped.

An example of such a relay can be the wiper or window relay. If the fan starts to work using the substitute relay, the old relay was the problem.

Conclusion

The car radiator fan relay serves an essential role in powering the engine’s cooling fans. Although this electric component is part of a car’s cooling system, it is easy to overlook it.

As such, you must master the simple ways to test a car radiator fan relay, as discussed here. Remember, if your car radiator fan relay is broken, you need to replace it immediately.

It will help you avoid problems in the cooling system that can lead to engine overheating and car damage.