e60eric

I have a 2010 528i with 62k miles. I’ve owned it for about a year and this problem just started happeningall of the sudden, making me think it was the battery. I changed the battery and had the battery “registered”by my favorite indy, but no resolution.

The HVAC fan speed increases/decreases randomly as I’m driving, andsometime goes off for long periods of time. If I try to override by turning the fan speed knob myself, no change. If the fan is running when I park and turnoff the engine, the fan keeps running until I get out and lock the car. The fan always stops when I lock the car. Otherwise, the car runs fine.

I took it back to my indy and he wants to charge $200 to completelydiagnose the car, and the $200 will not apply toward fixing whatever is wrong.

So, can anyone give me any clues as to what is going on? I’m at a loss, and I don’t have $200 to spareon the diagnosis right now.

Only Bimmers

There are typically 2 things that cause erratic blower symptoms. May try and search on them and see what others have experienced.

- Blower Motor Resister (common)
- HVAC controls (less common)

Gee_115

Your problem sounds like final stage unit( blower/fan speed regulator/ resistor). This is a common occurrence. I would go as far as to say save your money on diagnosis, just get the part (67636988452). The part cost about $50 if you shop around. The problem is getting to it, a very tedious job but can be done if you are an average DIYer. I have done it first try around 4 hrs, then around 2 hours. There is a DIY on the forum on how to do it. If you can't find it send me a message and I will post it.