Car Fan Won't Turn Off - What To Do? (2023)

A car fan is important because it pulls air through the radiator. If you notice that your car fan isn't turning off, you may be wondering what to do to tackle this problem. Fortunately, we have consulted experts in this field and here is what they have to say.

A car fan not turning off could be a result of various problems. Here are things you can do if you notice that your car fan isn't turning off:

  • Remove and disconnect the negative side of your car's battery.
  • Check your coolant level.
  • Check your temperature sensor.

If you discover that your car fan isn't turning off, you should deal with the issue as soon as you can so it does not get worse. Keep reading to get detailed information about how to tackle the problem of car fans.

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Car Fan Won't Turn Off - What To Do? (1)

What Should I Do When My Car Fan Doesn't Turn Off?

After parking your vehicle and turning off the engine, if you notice that the cooling fan is still running, you should do the following:

Remove And Disconnect The Negative Side Of Your Car's Battery

If you notice that your car fan isn't turning off you should stop your car battery from running down by removing and disconnecting the cable attached to the battery's negative terminal.

When the negative end of the battery wire is disconnected, and the automobile fan goes off, then the relay is the source of the problem.

Additionally, you can fix your fan relay by replacing it with a new one. Use the identical pin design. You can also use a digital multimeter to examine the cooling fan relay.


Car Fan Won't Turn Off - What To Do? (2)Car Fan Won't Turn Off - What To Do? (3)

View this digital multimeter on Amazon.

Check Your Coolant Level

You can also examine the amount of coolant that you have to find out whether it is low or not. This is to determine if the problem is due to low coolant.

You should also check for leaks. If your vehicle's coolant level is low, your engine may become hotter. This may result activate the vehicle's cooling fan.

Car Fan Won't Turn Off - What To Do? (4)Car Fan Won't Turn Off - What To Do? (5)

See this vehicle coolant on Amazon.

Check Your Temperature Sensor

Car Fan Won't Turn Off - What To Do? (6)

If the fan on your vehicle continues to run even after you turn off the engine, you should check the coolant temperature sensor because it may be faulty. The coolant temperature sensor provides the engine control unit with its signal.

Why Is My Car Fan Not Turning Off?

The radiator fan is an essential component of your vehicle's cooling system, and it may start malfunctioning over time. Here are the most common reasons why your car fan won't turn off:

(Video) Radiator Fan Running when Engine is Off

Low Coolant Level

Car Fan Won't Turn Off - What To Do? (7)

If the fan in your automobile continues to run even after you have shut off the engine of your vehicle, then the coolant in your car may be too low. The water pump is a potential source of leaks and when these leaks occur, your coolant reduces, and this may cause your fan to keep running.

Bad Thermostat Housing

The housing for your thermostat may be a possible source of the problem. There is a chance that the casing has leaked on it.

Faulty Radiator

Car Fan Won't Turn Off - What To Do? (8)

The radiator in your car is also a possible source of the problem. Your car fan may not turn off if your radiator is damaged. Cracks in the radiator can be a cause of the problem. Radiator hoses could also be where the problem is coming from. The upper and the lower radiator hoses on your vehicle are susceptible to wear and tear.

It is possible for the radiator hose and pipe to rust. When the pipe and hose get rusted, it automatically becomes damaged. When this happens, you car fan may not turn off.

Bad Radiator Fan Relay

The radiator fan relay is another possible cause of the problem, and you should examine it. The fan relay regulates the flow of electricity to the cooling fan. The automobile's fan will be affected if there are problems with the relay. For instance, the radiator fan relay can get stuck in the on position and become inoperable.

What Sensor Controls the Car Fan?

The coolant temperature sensor controls the car fan. The coolant temperature sensor is usually referred to as a negative temperature coefficient kind of sensor. The coolant temperature sensor sends a signal to the Engine Control Unit (ECU), which in turn receives the signal from the engine's coolant temperature sensor and controls the cooling fan.

How Temperature Sensor Works

The coolant temperature sensor is usually located close to the engine thermostat, making it function well. The tip of the coolant temperature sensor can be found close to the engine coolant.

(Video) Radiator Fan Won't Turn Off: 2014 - 2019 Silverado & Sierra: Bad Coolant Temperature Sensor Replaced

The sensor measures the temperature which the thermostat or the coolant releases. The temperature is then directed to the control system. After that, the computer of the car utilizes the temperature information to keep working or change the way the engine functions. It works continuously so the engine temperature will be kept at the right level.

When the control system gets the information from the sensor, it prompts the shutting off or turning on of the cooling fan. Also, it may give a sign that a richer fuel mixture is needed or open the gas recirculation.

Why Is My Car Fan So Loud?

You should be able to hear the sound of your radiator fan. However, it shouldn't be too loud. Some cars' fans are louder than others . Loud noises can be produced by restricted airflow around the car's radiator.

A fan's loud noises could be a result of a faulty radiator. Your radiator fan may also get louder if the blades are dirty. So make sure to clean them from time to time. Generally, your radiator fan may become noisier if your vehicle's cooling system malfunctions. Vehicles also tend to emit loud noises if the radiator fan belt is loose or broken.

How Much Does It Cost To Change The Fan In A Car?

On average, the cost of replacing a radiator fan is usually between $300 to $400. Sometimes, the cost of the radiator fan ranges between $400 to $450. The cost depends on the type of car.

In most automobiles, the radiator fan is easy to access and repair because it is mounted directly to the radiator. You can change the radiator fan on your own and save the money that would have been spent on labor if you are familiar with automotive tools and how they work.

However, you should avoid driving a vehicle with a broken radiator fan. If the fan is unable to supply the engine with cold air, the motor may get damaged as a result of an overheated engine. The expense of replacing the engine exceeds the cost of repairing or replacing a faulty radiator fan.

Car Fan Won't Turn Off - What To Do? (9)

Is There A Fuse For The Radiator Fan?

Yes, there is a fuse for the radiator fan. Generally, the fan uses a big fuse which is about 50A. There can also be another small fuse to the control module of the fan. You should bear in mind that if the fuse is blown, the wirings or fan may be having some issues.

(Video) Radiator Fan Wont Turn Off On Chevy Silverado 1500

The fuse for the fan is found in the fuse box, which can be located in the engine compartment, typically close to the fender on either the driver's or passenger's side of the car.

The fan fuse protects the entire component from any short circuits or voltage overloads. It does this by shielding the radiator's electric-cooling fans from potential danger.

Does The Thermostat Affect Radiator Fan?

Car Fan Won't Turn Off - What To Do? (10)

The thermostat does impact the radiator fan. If the thermostat were removed from the engine cooling system of a car and the fan was allowed to operate continuously, there would be a decline in its operations. The thermostat is responsible for controlling the flow of coolant to your radiator.

If the thermostat does not open when the engine reaches the operating temperature, the coolant will be contained within the engine block. This may cause the radiator fan to malfunction.

To Wrap Up

If you notice that your car fan is not turning off, you should try removing the negative side of your car's battery. You can also check your coolant level to see if it is low. After doing these things, if you are still unable to detect the source of the problem, you can consult a professional.

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Why is a fan still running when I turn my car off? ›

It's normal for some vehicles to have a fan run for a few minutes after the car is shut off, generally to keep the engine cool.

What to do if fan keeps running? ›

If your fan limit switch is set to AUTO but the fan continues to run without ever stopping, you'll need to call a professional. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced. Bad thermostat wiring.

Can low coolant cause fan to stay on? ›

If your engine coolant's too low, it means that the cooling fan will have to work harder to keep the engine at a normal temperature. To check the level, look for the coolant expansion tank in the engine bay. There are usually two marks on it – a minimum and maximum level mark.

What would cause a cooling fan to stay on? ›

Cooling fans stay on at all times

If the relay shorts internally, it may cause power to be permanently switched on, which will cause the fans to run at all times. Depending on the wiring setup of the vehicle, this may cause them to stay on even when the vehicle is off, which will drain the battery.

Will a fan drain my car battery? ›

Fans draw quite a bit of current! All you need to do to be able to answer this question is, find out how many amp-hours (AH) your battery is…and how many amps your fans draw. If your battery has 50 amp-hours(AH) of reserve, and the fans draw 10 amps, then your battery would last 5 hours with the fans on

How do you fix an overworking fan? ›

If your computer fans are getting loud, here are six troubleshooting tips you can try to fix the problem.
  1. Give Your PC Fans A Clean. ...
  2. Move Your PC Or Laptop For Better Airflow. ...
  3. Check Running Software. ...
  4. Use Fan Control Software. ...
  5. Replace Your Fans.
13 Jul 2020

Should engine fan run all time? ›

If it's an electric fan, no it shouldn't run all the time, only when engine temperature needs it. Can driving with one radiator fan not working damage the engine? It could if you're not dissipating enough heat. Fans are usually only necessary when not moving.

Why is my car fan not turning off? ›

Low Coolant Level

If the fan in your automobile continues to run even after you have shut off the engine of your vehicle, then the coolant in your car may be too low. The water pump is a potential source of leaks and when these leaks occur, your coolant reduces, and this may cause your fan to keep running.

Does cooling fan affect AC? ›

If either system is not operating at its full efficiency, the other could be affected. An example of this is the cooling fans–both the engine cooling fan and the air conditioning auxiliary fan. These fans are necessary to move a sufficient amount of air through both the radiator and the air conditioning condenser.

What triggers a radiator fan? ›

The engine temperature should trigger the fan to turn on. It will also turn the fan off once the engine has cooled to under 200 degrees. You may have heard of a part called the radiator fan switch or temperature fan switch. This is linked to a thermostat and works much like your home's HVAC system.

How long will a car battery run a fan? ›

Your 30 watt fan will draw about 2.5 amps at 12 volts (2.5 times 12 is 30). Assuming 90% efficiency from the inverter means that the inverter will draw 2.5/. 9, or 2.78 amps. A 50 Ahr battery will last 50/2.78 or 18 hours.

What kills a battery car? ›

Electrical devices or lights left running, a defective charging system or alternator, and extreme weather are some common reasons but maybe it's just time to get a new battery.”

What can drain a car battery overnight? ›

7 Things That Can Drain Your Car Battery
  1. You left your headlights on. ...
  2. Something is causing a "parasitic draw." ...
  3. Your battery connections are loose or corroded. ...
  4. It's extremely hot or cold outside. ...
  5. The battery isn't charging while you drive. ...
  6. You're taking too many short drives. ...
  7. Your battery is old.
17 Feb 2020

What is a common problem with fans? ›

With frequent usage, parts of a fan may loose. For standing fans or even ceiling fans, becoming wobbly or shaky is quite a common issue. Check if the screw fasteners are still tight or if there is any loose joint.

Why is my fan making a loud noise? ›

A ceiling fan making a grinding noise may be caused by unbalanced blades that make the fan wobble. Ceiling fan blades can become unbalanced by dust collecting on the blades when the fan isn't in use. Clean the blades by wiping them down with a damp rag to remove any dust and debris causing them to be unbalanced.

Why is my car cooling fan so loud? ›

Worn bearings, bent or broken blades, and unbalanced rotating assemblies can cause a fan to screech, howl, or otherwise make noises it shouldn't. Fortunately, switching out a worn fan for a new one isn't a huge ordeal.

What happens if AC and fan are on together? ›

Using a fan with your A/C can significantly reduce the hot temps in your home – and reduce your energy bill. By positioning fans near window unit A/Cs or near central air vents, you can circulate the cool air over a wider area.

Does the thermostat control the radiator fan? ›

The thermostat found in the cooling system will control many of the electric fans. When a certain preset temperature has been reached by the car engine, the radiator fan will begin to cool the engine. The fan will turn off eventually if the temperature goes below the preset engine temperature.

At what temperature does a radiator fan turn on? ›

Around 200 degrees Fahrenheit should cause your radiator fan to turn on. Check to see if you can hear the fan if you notice that your car is running hotter than usual or that it is overheating.

How do you test a fan switch? ›

Testing: Before checking the radiator fan switch it is important that the ignition is switched off and the engine bay has had time to cool down. Once cool, disconnect the switch from the radiator fan, and connect the car battery to the fan motor. If the fan operates this suggests that the fan is not the problem.

Why is my fan running when my thermostat is off? ›

If only the fan is running when the AC isn't, there may be a faulty relay switch stopping the settings you enter on the thermostat from being communicated to the fan. It's also possible there is another wiring issue or short circuit preventing the on and off commands from going to your fan.

Can a fan stay on all day? ›

Some people fear that a ceiling fan will overheat and catch fire if left running overnight; however, these fears are unreasonable. Ceiling fans are designed and manufactured to run for hours on end, and if you invest your money in a reputable brand, you shouldn't have any fears.

Why does my blower motor not shut off? ›

On your thermostat, look for the fan settings. There should be two, “ON” and “AUTO.” If it seems like your furnace won't turn off, the thermostat may be set to “ON” for the blower. Toggle the switch to “AUTO” so your furnace's blower fan only runs during a heat cycle.

What is a stuck fan relay? ›

If the relay gets stuck in one position, it can prevent the air conditioner from turning on or cause it to turn off unexpectedly since the ac fan and blower motor won't receive the necessary power to operate. A faulty relay is the main cause of electrical power problems with your HVAC unit.

Does the thermostat control the fan? ›

The fan setting on your thermostat controls your HVAC's system blower. The blower helps circulate hot or cold air throughout your home until the temperature on the thermostat is reached. There are two settings on your thermostat to control the fan – auto or on.

Can a fan overheat? ›

Conclusion. While a ceiling fan helps you cool down, its system itself goes through a process that can cause it to overheat. Ultimately, electrical energy is converted into heat.

Is it OK to leave a fan running? ›

Leaving fans running when there is no one to benefit from the air is simply wasting electricity. Also, most fans run on motors that produce heat when running. This heat is small, yes, but a room where a fan is left running is literally wasting energy and adding heat to your home.

How long do fans last? ›

Most fans are designed for about 30,000-50,000 hours of continuous use – or 3.5-6 years. However, this does not mean that all fans will last the same amount of time. A case fan, for example, will likely last for 5-6 years where as a laptop fan may last closer to 10 years.


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