My radiator fan has been refusing to turn on as of late. What are all the major components related to the radiator fan system and what is the best method to diagnose which component may be faulty?
Thanks for any input!
-Luke

 

start with the relay. If you jumper you can see if the motor works. Could also be the temp sensor (you can measure resistance to see what's up) - anything else going on - temp gauge reading low? check engine light or car running oddly warm or cold? Most likely its either the relay, the electrical connectors or the motor.

 

There are two wires going to the center connector on the relay. One is Yellow/White and the other is Yellow. You can test the relay function by removing that connector and individually grounding the pins associated with those two wires on the relay. One should turn the fan on low speed and the other should trigger high speed but I can't remember which is which. As long as both speeds work then the relay, and by extension the fan motor, are both fine.

If both speeds work on the fan and it still doesn't turn on in normal operation then there is a problem with either the wiring from the ECU to the fan or the ECU itself. The relay itself is a much more common failure.

Unless the air conditioner is on and operating or the car is stuck in traffic it is common for the electric radiator fan to not run very often. The air conditioning should alway turn the fan on if it is working. Just turning the A/C switch on isn't enough to trigger the radiator fan though, the high pressure switch on the A/C system is what tell the ECU to turn it on and if the air conditioning is not operating properly it will not trigger the fan.

...Lee