I experienced the same problem:
- mist coming from vent
- drivers side cooler air, passenger side warmer air (regardless of center vent mixture control)
- higher fan speed on auto (presumably because the passenger side is heating and the driver side is cooling)... I believe this to be an ancillary side effect
- on two different days (in the past 4 months), the fan would make a lot of noise, but not actually blow significant air. I replaced the FSR this morning... I believe this issue is separate from the rest, so I'm hoping the new FSR resolves it. PS -thanks to this forum for the FSR DIY... took me about 20minutes to do, and I am not extremely technical.
- no smells/odors

NEXT STEPS:
- I am torn between "recharging the AC" vs. "replacing the Heater Valve"
- I figure the $$ spent to diagnose it would be better spent just replacing the two components listed above.
- tried "tapping" the heater valves physically with a wrench - no luck.

Any thoughts?

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Current Vehicles:
2006 BMW X5 4.4i, Premium, Sport, Cold Weather, Rear Climate, Rear Heated Seats, PanoRoof, Air Suspension, Comfort Seats, Nav, Alpine White with Light Poplar and Truffle Brown Interior

2007 BMW 335i Coupe, Premium, Sport, Cold Weather, Space Grey With Dark Burlwood & Black Leather