Here is my problem. I have a '85 735i and after using the heater and then turning it off I still get hot air comming out if the defrost vents eventhough everything is turned off. If I go to use the A/C then I get A/C comming out the defrost vents. Turn that off and still get air comming out the defrost vents. This air only comes out when i'm moving. I assume that something isn't closing and therefor a vaccum leak but where should I be looking first. I've been to a BMW dealership but those guys don't know their ass from a hole in the ground.