Blower motor runs but no airflow up front. Rear blows fine.

[linuszz]

I'm a new owner of an E90 M3 (2008). Just did the head unit/carplay upgrade, rear camera, and fold down seat retrofit (great so far!).

However with the weather changing I realized that the blower for the heat (or AC?) doesn't work right. All the controls seem to work but no air comes out from any of the front vents. Well maybe a tiny bit but not really. The rear blows strong. The fan speed controls work and you can hear/feel the blower turn on and increase in speed. The controls for foot/mid/windshield all light up properly just nothing comes out.

I'm thinking that it might be the blower motor final stage / resistor / regulator thing. I'm wondering if I should just purchase one and hope that is the culprit, or if anyone can say "yup, that's very likely the problem"or if anyone knows how to test it to confirm before purchasing a replacement. (I pulled out the regulator last night).

It seems like there must be a motor to control/open some diverter of some kind to open supply to those vent locations. I guess I'm wondering if the regulator/resistor also controls the diverter or just the fan speeds?


Thanks in advance!

P.S. While replacing the head unit, I did end up pulling down the Junction Box Electronic Control Module (JBE) when I disconnected the battery and locked myself out of the trunk. But that is all buttoned up and working great. All fuses checked.