Hey X5FX - did you ever get your A/C issue resolved? I have a 2007 4.8i and with the temperatures here in TX starting to heat up again, I came across this same issue today. On a drive between Dallas and Austin, when I had the rear A/C on, I had almost zero air flow in the front. Even on "Max" A/C. I had to continuously switch between front and rear so that I wouldn't sweat too bad and so that my 3-yr old in the back wasn't too uncomfortable. Given the cost of this car, this is unacceptable.

Oddly, after getting home and allowing the car to be off for about 30 min, I tried it again and the air flow was even throughout the car. So a reboot of the system and it's working at the moment. Is this a computer issue? Maybe the A/C program is buggy, resulting in the "possessed" behavior of the A/C system.