What to know about the Thermo Coolant Fan Switch:
The cooling fan on your car only operates when the engine temperature is hot due to a thermo cooling fan switch. It is mounted on the engine and senses the temperature of the engine as a simple electrical two-wire switch. When the temperature reaches the set value for the switch, it completes a circuit inside that starts the cooling fan operation. When the temperature drops below a set threshold, the cooling fan turns off. If the thermo cooling fan switch is defective, the cooling fan may run all the time even if the engine is off, or the cooling fan may not turn on at all when the engine temperature is too high.
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Facts to Note:
Your engine’s thermostat is essential for preventing overheating.
The cooling fan can continue to operate even when the engine is shut off.
How to Fix:
The coolant is allowed to cool and then drained
The faulty thermo coolant fan switch electrical connector is separated from the switch and the switch removed.
The new thermo coolant fan switch is fixed and the electrical connector is connected
The coolant is filled and coolant system is bled of air
The engine is ran and cleared of codes and road tested for proper cooling fan operation
READ ALSO: HOW TO KNOW A BAD THERMO COOLANT FAN SWITCH
The cooling fan switch will likely last the life of your vehicle, though it can fail unexpectedly as electrical devices are prone to do. If that happens or if you suspect the thermo cooling fan switch is faulty, have one of your expert mechanics analyze it.
Common symptoms indicating you may need to change the Thermo Coolant Fan Switch:
Check Engine light is on
Cooling fan isn’t turning on
Engine temperature is above normal or the engine hot warning is on
Importance of this service:
Because catastrophic engine failure can occur from overheating, it is vital to change the thermo cooling fan switch as soon as it has been analyzed as defective.