New to BMW and went here after having some electrical issues with my 2007 Z4. Well, it turns out it was just a marginally bad battery (despite having it checked at a couple of auto parts stores since that's what I suspected) that was causing the computers to limit the blower speed due to lower voltage output. Sometimes I miss my old '70 El Camino... though tuning a carb isn't fun either.
Paying shop labor to replace makes me cringe since it's so easy - but convenience counts too. However, they also justified the labor saying the battery needed to be registered (not sure I believe that from the forums - E85/N52 should be one of the last designs without that 'feature') and charged for telling me they could *not* change the programming in the computer from a 90mA setting to the 80 mA batteries which were the only ones available makes me feel less-than-five-stars.
Note - the new battery is much larger than the old (which was installed by a previous owner, obviously from an auto parts store) and didn't have a mA rating, so that might have contributed.
Also noted some other work that needed to be done, but wasn't aggressive about doing it now which I appreciate. And a nice local shuttle that got me to work and back. So I'll be back for any new issues I can't deal with on my own.