I have an 2007 sport sedan 3 and here about 3 months ago my upper left air vent quite blowing air. Center and right vents work fine. This happens with the control in any position. Vent, recirculate, both in mid setting. Doesn't work on a/c or heat. Only on upper left. Any info will be appreciated.

 

'Sounds like the simple problem of the hose coming off that goes to the vent, either on the heater box or at the vent itself. Since you feel nothing at the vent, my guess would be the heater box side.

 

Virg where is the Heatewr box located and any pictures would help. I suspect it's behind the center console where the shifter is. When you move the selector for the air control to the different positins are there vaccum control doors for each outlet or is there doors on the before mentioned Heater box.

 

Correct! Center dash beneath/behind the console as in most cars.
It's possible that a linkage to a vacuum "motor" came undone too. Your best bet is to just dig around under there and see what you can see.