How the coolant and AC fans work?

GEORGESELHAGE

MEMBER
2002 TOYOTA TARAGO
160,000 MILES

How the coolant and ac fans work. Do they switch on together or separately. Are they activated by coolant thermo switch or by temperature sensor. Many

How the cooling fanss work together or separately. Because I noticed the twin fans in front of the radiator switch on together and switch off together. Supposed fan 1 to come on when coolant hot and fan 2 to come on when we run the aircondioning system.I worry the temperature sensor faulty because the temperature gauge needle rises up from cold engine to the middle of the gauge when engine warms up and I measure the resistance of temperature sensor at hot coolant it is 200 ohms

2 Replies

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Both fans can come on together if the temp gets high enough. Otherwise, one will come on based on the temp sensor reading and the other will come on with the AC.

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Friday, November 8th, 2013 AT 5:11 PM

GEORGES EL HAGE

MEMBER
2 POSTS

Thank you very much mr jacobandnickolas fot the answer, but both fans come on at the time and turn off at the time with or without aircondiong on , never one fan switch on alone do you think I have problem with the computer module or temperature sensor. My car is Toyota tarago 2002 acr30. Because I lost head gasket not long time ago I insist on temperature sensor to be faulty. Can I replace it please advise