Blower fan runs slow/stops


My blower fan does not run on high, only 3 bars. When I come to a stop, the fan goes off completely, briefly. Sometimes after running for awhile, it will come on full speed. Thoughts?

Replace the fan


I’m not a mechanic but it sounds like the fan motor is responding to variations in alternator output, i.e., greater output when the engine is turning over faster as opposed to idling. You didn’t say what year your 325 is but either have a dealer or a good independent mechanic look at it, depending on whether it’s still under warranty.

Next time the fan stops running, bump it with your fist. If it starts running again, the contacts inside the fan are worn and it needs replaced.

Thanks, will do if I can figure out where the fan is, lol.

The blower speed is determine by the automatic temperature control computer, if you lower the temperature setting or over ride the fan speed setting, does it increase?

No, no effect by changing temperature.

Well, they’re usually somewhere above the passenger side footwell, up under the dash, encased in a plastic housing. BMW does things odd sometimes, though, so it may be in the trunk (kidding)!

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Yeah, correct! Like the $800 battery!

It’s most likely the final stage resistor for the fan( white plastic part situated below the fan itself). if it’s an E90 there was a recall for wiring overheating in some markets.