My radiator fan does not engage when the engine overheats, but it turns on when AC comes on. What can be a possible culprits? My car is 2006 R52 Mini Cooper S.

Thanks!

 

There is a HUGE, LONG, INVOLVED thread on this issue. Use the search function and you will be amazed.

 

Going to move you to the Stock Problems/Issues area.

On the AC, are both the low and high speed working? On the overheat, as the AC is tripping the fan and the temperature sensor is not, it may be a sticky relay. Item # 23 in the below thread has information on the relays that are located in the engine compartment fuse box.

https://www.northamericanmotoring.co...questions.html

 

Thanks for the information.
On the AC, only high speed seems to be working, but when I turn off the overheated engine, high speed fan doesn't come on. Do you think it's bad relay/ resistor or something else?

Thanks in advance!

 

Try checking your coolant temp sensor. It's not a pricey part.

 

I was just wondering would bad coolant temp sensor trigger CEL?

thanks