Car Fan Won’t Turn Off: Why Is That And What To Do? (Explained)

You may find yourself in a situation where your car fan is still turned on even after shutting off your car engine. This is a situation drivers would find themselves in often. If you want to know what to do about this situation, keep reading to be enlightened.

This article is for those who have no idea what to do if the car fan is not turned off. This happens even after your engine is turned off. Drivers are knocking their heads about what could be the possible reasons. 

With this article, you will know the reasons why your car fan will not turn off. You will also know basic troubleshooting and what to do if your car fan stays on even with a turned-off engine. And so, without further ado, let us start talking about the matter at hand.

Car Fan Won’t Turn Off

11 Reasons Car Fan Keeps Running When Car Is Off

If you turn off your car’s engine, it is typical for the engine cooling fan to keep running even after a few minutes. It would usually and typically run for a few minutes before turning to a stop. That is just normal. 

So you do not have to worry if you will notice your car fan running for about a few minutes after going into a stop. That is how it usually happens. 

If you own a BMW or a Mercedes-Benz, the car fan can run for about five (5) minutes or more before going into a stop. However, there are cases where the car fan will not stop at all. You may be encountering some issues with the electrical, and it can cause the car fan to stay on, and it can even drain your car’s battery. 

If your car’s engine is running, the coolant will circulate coming from the car’s engine and will then flow into your engine’s radiator. This is where the heat will dissolve. So if your car’s engine is turned off, the coolant will not circulate in the engine. 

As a result, the heat will stay trapped, and it will then take a very long time for the engine to cool off. If you turn off your car, turning the coolant fans on will help the engine to cool down. 

There are also some other reasons why your car fan will keep on running even if your car is turned off. Here are some of them.

1. Heater Core

The seventh possible problem could be your heater core. First, check your heater core because your heater core might have leaks.

2. Coolant Temperature Sensor

The second possible problem could be your coolant level temperature sensor. If your car fan stays on even after the engine is turned off, you may have a faulty coolant temperature sensor. 

In modern cars, most of them are controlled by an engine control unit or ECU. The engine control unit or ECU is getting its signal from the coolant temperature sensor.

3. Leakage In The Coolant

The fourth possible problem could be your coolant. Your coolant can have leaks, and these leaks can be from the water pump.

4. Thermostat Housing

The eighth possible problem could be your thermostat housing. Your thermostat housing can have leaked on them.

5. Coolant Level

The first possible problem could be your coolant level. For example, if your car fan does not stop running even after you have turned off your vehicle’s engine, you might have a low coolant level.

6. Radiator

The fifth possible problem could be your radiator. If your radiator is defective or has cracks, it can cause your car fan not to turn off.

7. Radiator Hoses

The sixth possible problem could be your radiator hoses. Your upper radiator hoses and your lower radiator hoses can get worn up. It can cause defects on your car fan, like not turning it off.

8. Wirings

The eleventh possible problem could be your wirings. You might be short on the electrical wires. Your electrical wiring can also be faulty.


The third possible problem could be your PCM or your ECU. Your PCM or your ECU can be defective. Have both of them check to find a resolution.

10.  Coolant Bypass Pipe

The ninth possible problem could be your coolant bypass pipe. Your coolant bypass pipe can get corroded. The rust can cause damage to the pipe.

11.  Radiator Fan Relay

The tenth possible problem could be your radiator fan relay. You need to check your radiator fan relay. 

The one that controls the power to the cooling fan is the fan relay. If there are issues and defects with the relay, the car fan will get affected. For example, the radiator fan relay can be frozen in the on position.

How To Fix That The Fan On Your Car Won’t Turn Off?

It is essential to know how to fix it if your car fan does not turn off after the engine. For example, suppose the fan in your car will continue to turn on and run for about thirty minutes or more than thirty minutes. In that case, you can remove and disconnect the negative side of the battery’s cable so that you can prevent your battery from getting drained. 

After removing the battery cable’s negative side and the car fan turned off, you can conclude that the relay is the cause. You can also check for your coolant level. First, you have to check if you have a low coolant level. 

Check also for signs of leaks. For example, if you have a low coolant level, you will have a hotter engine, which can cause the car fan’s activation. You can also do some troubleshooting steps. 

You can replace your bad fan relay with a good one. Have the same pin design. You can also use a digital multimeter so that you can check the cooling fan relay.

Car AC Fan Won’t Turn Off: What To Do?

You might also be having difficulty with your AC fan. You might find that your AC fan will not turn off. The prevalent reason your air conditioner will not turn off is that a stuck relay can keep the circuit closed. 

If you have found out that your relay is not the problem, you might check your thermostat because it might need replacement or it can be short-cabled. The first thing people do is to call for an expert or a service technician immediately. They will also replace your components, but you must check your thermostat settings first. 

You have to set the desired temperature just above the room’s temperature so as not to turn off the air conditioner. Then, if the fan is still blowing even after a few minutes, recheck the thermostat and ensure that the fan is not set on. If you are confident that all your settings are correct, you can now contact a service technician so that they can do more troubleshooting and they can resolve the issue. 

You might be experiencing a stuck relay. The relay in your air conditioner unit assists in opening and closing electrical circuits so that they can turn on the components like the car fan. For some time, the relay can cause failure and have defects. 

You can also have a malfunctioning thermostat. If your thermostat is malfunctioning and faulty, it will cause your air conditioner fan to run non-stop because it will not know when they have reached their desired temperature.  

Car Engine Fan Won’t Turn Off: What To Do?

Your engine cooling fan is working with a series of circuits. The coolant temperature sensor will indicate to the computer to turn on the cooling fan or turn it off. If the temperature reaches or exceeds a specific temperature level, the computer will automatically turn the cooling fan on. 

The temperature is usually about two hundred fifteen (215) degrees. So you can open the hood of your car and then look for the location of the fuse relay box. This is usually on the driver’s fender well. 

If you have located it, remove the lid. After that, look for the inside of the lid and then for the mapping of the fuses and the relays. Finally, take the cooling fan relay out of the box and replace it with a new one.


In summary, many people do not know what to do if their cooling fan does not turn off, even if they have turned off the engine. There are many possible reasons why the car fan will not turn off after shutting the engine off. You need to check for these possible reasons above and find out the specific reasons; only then can you find a resolution.

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more