Magic Blower (HVAC)

Hello all,

My first post here. I live in Germany and drive a 2008 525d. Have been driving the car for three years and everything has been great. Raked up 100K miles. I have been taking the car to the dealership for maintenance because I like to trade it in soon. Lately a first issue arose, which I like to fix myself if possible.

The issue is, after driving for approximately 1 hour and 15 minutes, the HVAC blower starts blowing harder, then softer again, the harder again, and softer, and on and on. Sometimes itkeeps blowing hard, sometimes it goes back to soft again.

My 1989 Porsche 928 has a resistor pack which controls blower speed and if that pack goes south the same thing happens. I have no idea how blower speed is controlled in my E60 though.

Anyone have encountered this problem and any ideas to fix it?

Thanks

Had a similar problem and changed this one (Nr 2) (545i) :

http://www.realoem.com/bmw/showparts...55&hg=64&fg=40

Does it happen in AUTO mode or at manually set speeds?

Originally Posted by ahnders

Had a similar problem and changed this one (Nr 2) (545i) :

http://www.realoem.com/bmw/showparts...55&hg=64&fg=40

Thanks, I'll look into it. Good site btw.

Originally Posted by audiophool

Does it happen in AUTO mode or at manually set speeds?

D'oh! Good call. in AUTO mode. I played around a little bit with the controls, setting the blower speed manually to different levels. Blower speed stayed constant at each level. I also switched between the AUTO settings soft, middle and intensive. After that I set it to soft AUTO mode (this is my default setting) and everything was good again. So what does that say?

Maybe a wonky solar load sensor or some other sensor?

Originally Posted by audiophool

Maybe a wonky solar load sensor or some other sensor?

Hmm, I don't know where any of those are located