Runaway aux cooling fan

[spmagee]

Help! My car wouldn't start yesterday after a very cold night (for coastal SC) and when I opened the hood I found that the aux cooling fan was running for no reason, and now the battery is deader than dead.

Is the running fan a reason or a symptom?

Has this happened to anyone else out there?

Thanks,

Sean

'97 E36 328i 5-speed

[Jeron]

I would suspect the fan relay, because I don't think the fan is supposed to run at all with the car off.

I would disconnect the battery, charge it and reconnect. Hopefully the fan will start running again. If so tap on the relay with a screwdriver to see if it ticks off. If it doesn't pull the relay and the fan should stop. Then test the low power trip of the relay to see if the relay is indeed being tripped or if the relay is just stuck.