I have a 1986 735IL Any advise on why the dash vents for A/C don't change properly. 90% of air goes to defrost vents and rest to floor.
that has a knob that you turn to change the vents, right? it's possible that the rod attached to the knob came loose, do you feel any resistance when you turn the knob?
Same model as mine. Same problem. The vacuum-operated actuators in your A/C unit (bottom-most stack under the centre console) are inoperative. Instead of the evnt doors opening on command and directing air to the face vents on the dash, the system has reverted to the default position which is always defrost. Labour intensive to remove heating control module to dig down to unearth A/C module. $1600 at my BMW specialty garage.
