How to Test Radiator Fan with Car Battery? Steps

The radiator fan is responsible for cooling the engine system. It draws cool air through the radiator and to the engine. Now, if you experience overheating, this may be caused by a bad radiator fan.

Knowing how to test your car’s radiator fan, especially with the car battery, can be a lifesaver. Our professional mechanic has compiled this DIY guide to help our readers how to test your car’s radiator fan. Let’s dive right into it!!!

test radiator fan


There are different ways to test your radiator fan performance, one of which is through the car battery. To do this, you do not need any special tools. All you need are the proper steps, and you are good to go. Here is how:

Below is an easy-to-follow step on testing aradiator fanwith a car battery.

1. The first thing you will need to do is find the cooling fan. It is usually located next to the radiator; consult your vehicle’s manual if you are still looking for it.

2. Find the connection and disconnect it.

3. You will need to connect the fan directly to the battery. To do this, you will need jumper wires.

4. Once you get a jumper wire, plug it into the fan and connect it directly to the battery.

5. If the fan motor spins, it is working fine.

6. If the motor does not spin, you may have blown a fuse or damaged the relay. The issue could also be traced to a damaged connector or frayed wires.

Testing Radiator Fan YouTube


Another way oftesting radiator fanis by using a multimeter. A multimeter is a standard tool used by both professionals and DIYers.

It is a device that measures the electric current or voltage in any electrical component.

Below is an easy-to-follow step for a radiatorfan testusing a multimeter.

1. The first in this process is finding the fuse box on your car. The location of the fuse box differs from the vehicle.

The common place you can find the fuse box in most cars is under the hood. You could also consult your car’s manual to make it easier for you to find it.

2. With the help of your car’s manual, locate the radiator fan fuse.

3. Once you find the radiator and the fuse, it’s time to set the multimeter. Most vehicles use a 12V battery, for a running car it can show 14v car battery and you can confirm this by checking the instructions on your battery.

Once confirmed, set the multimeter to Direct Current Voltage (DCV). You can also select the best number range for your 12V circuit.

4. Proceed to ensure the engine is properly switched off. If you do not do this, you may not get an accurate test of the radiator fan. Also, you could cause a short circuit.

5. If your vehicle uses an under-dash fuse, connect the black lead (negative) to the negative battery terminal. Then connect the red lead (positive) to the fuse.

6. Observe the multimeter reading; if it reads within the value of 12V, then the fuse works fine. If the reading values 12V on contact and 0V on the other, the fuse is blown.

7. If both contact values read 0v, there is no power in the fuse. It means you are not connecting the multimeter properly; you will need to do it properly.

8. If the problem with your radiator fan is its fuse, you may need to have it replaced.

By adequately following this step, you now know how to test radiator fan relay. Ensure to follow all safety procedures and have assistance if you can.  


There are many ways to know that you have a radiator fan broken without knowing howto test a radiator fan. By observing your vehicle for some noticeable signs your vehicle is showing, you can easily detect your radiator fan issue.

1. Engine Overheating

The primary function of the radiator fan is to cool the engine. The engine will not receive adequate cooling when it is not working correctly,. When this happens, your engine will begin to experience overheating.

Once you start noticing that your engine is overheating regularly, the cooling system is not working. You should check the radiator fan.

2. Loud noise from the radiator fan

Another sign is the radiator fan making noise. When you hear a strange noise from the engine bay, you must immediately investigate where it is coming from.

When part of the radiator fan assembly is broken, it makes noises when the fan tries to spin. If this problem is not repaired, it could lead to further damage and a complete stop in the functioning of the fan.

3. Reduced Air Conditioning

When the radiator fan is not working as it should, the heat builds up in the engine system, affecting how the air conditioner works.

The AC has to work extra to ensure the vehicle’s interior is excellent. You should check the cooling system and radiator fan when your AC is not cooling.

4. Temperature warning light

You must pay attention to all the vehicle’s warning lights displays on the dashboard. The temperature warning light indicates something is wrong with your cooling system, which could be traced to a faulty radiator fan.

The warning shows when the engine exceeds a specific temperature or becomes too hot. It is why you should not ignore the warning.


Following our guide, you should be able to test your radiator fan performance easily using any of the above methods.

You can now quickly test your radiator fan if you notice any of the listed symptoms in your vehicle.

Try checking for broken fan assemblies, as it could cause the fan to slow down or stop working. Thank you for reading.

Akindayini Temiloluwa

I am Akindayini Temiloluwa, an automotive expert writer and car enthusiast. I have over three years of experience in the automotive writing niche and have completed over 300 pieces of content from 50 projects. I have vast knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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