How Car Engine Cooling Fan turns on.?

Either the fan turns on by temperature sensor or by Thermostat?
How Car Engine Cooling Fan turns on.?
Temp sensor. It is often called WATER TEMP SENSOR.





The thermostat is a mechanical device that physically open and close to control the flow of coolant. It is NOT an electric device.








Good Luck...
How Car Engine Cooling Fan turns on.?
either electrically with a temp sensor or by a fan clutch the ones with fan clutch are normally on v8 because the fan is directly infront of the engine and basically mounted on the engine electric one are remotly located away from the engine and will have connectors goin up to it
Reply:normally there is a temperature switch on the engine the tells the computer the engine temperature,the computer then decides when to turn on the fan, the computer at the right time closes the contacts of the fan relay,the fan now if its any good will come on often when i wiggle the wires at the fan it will come on or i jumper wire between terminal 30 and 87 on the fan relay to check fan operation