Jens, my 84'733i has vent problems. if i rev the engine the vents go into defrost when its on a.c. i then have to turn the temp. wheel to hot and slowly it starts to come out of the front vents, then i turn the temp. wheel back to cold. BUT! then if i rev the engine or really take off fast it goes back into defrost and i have to keep playing this game with the temp. wheel.....any suggestions? thanks...mike do you repair parts? e-mail: mike10s2000@yahoo.com