Over the last week my 2003 MCS has had a perplexing problem of the engine cooling fan starting spontaneously while sitting in the garage with the ignition off. When I have witnessed the episodes they have lasted 5-10 min then shut off by itself. But this morning the battery was dead and when I put on the jumpers the fan started up. The cover of the relay box near the ecu shows two relays for the cooling fan, I & II. The fan stopped only when I removed the number II relay. Does this indicate a faulty relay (easy fix) or a problem deeper in the electrical system (bad news). Any insight would be appreciated.

Thanks,

Mike

 

If you can hear the relay 'click' when it's installed, the problem is upstream of it, i.e. something (ecu) is turning the relay on. If you cant hear the click, than the relay is shorted. Swap it with an identical neighboring relay to confirm.

 

Greatbear, Thanks for the help. Mike

 

Hey Spinner, what turned out to be the cause of the problem on your Mini? My wife's 02 woke up with a stone cold battery this morning and when we went to jump it, the fan is stuck on...... Looks like I need to do some detective work and wondered if you had any advice from your experience.

Cheers,
Lloyd

 

Well..... this is a strange one.... got my wife's car home (via tow truck) after the fan stayed on all night and ran the battery down. Started messing around with things... jumper cables on it so I have power, I removed both relays that have a fan pictures (R3 & R4) and removed the 30 amp fuse that has the picture of the fan... the dang thing continues to run anyway...... Unplugged the main power to the fan and of course it stops, but plug the power back in and it starts up again...

All of this with no key in the ignition, let alone running or hot. There is obviously another path for power besides the path through the relay and the fuse. New Country Mini service department in Hartford called me back and says it sounds like the controller on the fan, but of course no real advice from them unless I bring it in for full diagnostic service... 50 miles away and not under warranty anymore at 65,000 miles.

Anyone have any advice for how to narrow and identify the real cause so I can consider replacing parts myself?

Thanks,
Lloyd

 

The problem turned out to be an intermittant bad relay (#2) to the engine fan. They are designed to run for a bit after the ignition is turned off if the engine is especially hot so the the fan is wired outside the irgition. In my car it was the seconday relay and taking out the relay solved the problem until I was able to get to the dealer for a replacement.

Mike