I have a 86 Mercury Sable, with 39000 miles. Yes original miles. The problem I am having is the air controls, I can only get it to blow from the dash or the the floor, they switch fine when I turn them to that setting. If I try to get it to blow from the front vents it will not do that, it will come out the dash. Is it a vacuum problem? Where should I start my search? I was told it could be a bad actuator, not sure though. Any help would be greatly appreciated.

 

could possibly be a broken door in system... it is problem with where the vacuum servo breaks where the arm connects to the door usually...