National average cost of a Cooling Fan Switch for popular vehicles:
What is a cooling fan switch and how does it work?
A cooling fan switch is a component of a vehicle’s engine cooling system. It is typically used in conjunction with an electrical cooling fan assembly.
To keep your engine from overheating, liquid coolant is circulated through the engine block. There, the coolant absorbs heat before it is pumped out of the engine and into the radiator. Air passing through the radiator allows the heat to dissipate into the atmosphere.
But air does not pass through the radiator when your vehicle is not moving. Therefore, a fan is used to move more air across the radiator cooling fins.
And yet, the cooling fan is not always needed. It only needs to turn on when your engine reaches a certain temperature. Mounted on your engine, the job of the cooling fan switch is to sense engine temperature and turn the fan on and off as needed.
How can I tell if my cooling fan switch needs to be replaced?
In order to ensure that your engine operates within a designated temperature range - usually somewhere between 185-220 degrees Fahrenheit - the cooling fan must be operational. The cooling fan switch is the component that operates the fan on many vehicles. When the switch goes bad, the fan will either work intermittently or fail to work altogether.
If the coolant fan switch fails, your engine can overheat. You might see the temperature gauge rise or a temperature warning light come on. Your engine might run sluggishly as it goes into “limp mode”. And the check engine light might come on.
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The replacement procedure for the cooling fan switch differs from one vehicle make and model to the next. Therefore, it is necessary that a technician not only procure the correct replacement part, but also determine its mounting location. The switch is often mounted on the engine block, but not in the same location on every engine. Some manufacturers even mount the switch in a radiator hose.
Once the switch has been located, any components that are in the way of access to the switch must be removed. From there, the technician will do the following
Drain some (or most) of the engine coolant
Unscrew or detach the cooling fan switch, taking care to avoid breaking it in its mount
Remove the switch and insert the new switch
Tighten or fasten the new switch in place
Reinstall any components removed for access
Top off the engine coolant
Bleed air from the cooling system before putting the vehicle back into service
OTHER QUESTIONS CUSTOMERS ASK
What causes a cooling fan not to come on?
If your cooling fan does not come on, a number of factors could be the culprit. For instance, a blown fan relay or a bad cooling fan switch could each cause the problem. Frayed wires could also prevent the fan from working. Even an engine that runs cool keeps the cooling fan from operating.
Where is the cooling fan switch located?
A cooling fan switch is usually mounted somewhere on the engine block. The precise location is different from one vehicle make and model to the next. Some vehicle manufacturers, such as BMW, even mount the cooling fan switch in the lower radiator hose.
Does the thermostat control the cooling fan?
The thermostat in your engine is designed to open and close the flow of coolant as engine temperatures rise and fall. When the engine gets hot, the thermostat opens; when it cools off, the thermostat closes. The thermostat does not directly affect the cooling fan, but it may do so indirectly, especially in a vehicle where the cooling system components are controlled by a computer.