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Fan cooling relay fans do not come on when thermal switch is plugged in un-plug it then they work

I checked the relay with a 12v power source and I applied power to number 1 and 2 terminals and ran my ohm meter from the 3 and 4 terminal,well it clicks like it suppose to but it has no resistance when I check 3 and 4 pins

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Year make and model. 3 and 4 wouldn't have resistance. they go to 2 separate things. You would have to check 3 and 4 for power and ground. At the relay , you should have 2 power points, with the key on(we'll say 1 and 3). the others will be ground, One will go to ground(the fans). the other is grounded by the ECM. Which only grounds it after around 200 degrees. Resistance is checked with the power off and checking between the relay and ignition, ECM or fans.

Posted on Dec 10, 2014

Testimonial: "So what you are saying that 3 and 4 ground the cooling fans.So how should I check it to see if it is a relay problem"

  • Randy Ohler Dec 10, 2014

    Sorry Doris, I misread some what. If you are checking the relay, then when you power and ground it, it will click. And yes you should have ohm readings ( goes to 0 or close). If no readings, the relay is bad. Ohm meter reads OL( out of limits). the relay is bad. I haven't done it this way for some time. It is way easier to swap relays and test, than to do an Ohm test on them.



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SOURCE: 2002 Mini non S cooling fan not working, No power

Hello there, i think i can solve your problem , check fuse 3 under the hood it should be a 5 amp if its not the check the closest 5amp to that, check to see if it blown if it is blown then your power steering fan is now working as well as the cooling fan, if that is the cause you will need to replaced the power steering fan as well as the 5 amp fuse, and also in addition you will need to sepate the power steering fan from the cooling fan. Mini parts sells a harness to separte the 2 fan

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