chemlab

I've had a problem with my heat for a few years now, no matter where I set the air to go, it always keeps comming out of the main vents. This is becomming a problem as my windshield defroster has no air pressure to clear it up during the winter. At one point I asked the local ford dealer, and they quoted me $800 to repair it. I laughed at them and left the dealership.

So I did some digging around and found 3 vacuum motors hooked up to blend doors. All of the motors seems to work perfectly through their full range of motion. I know one I found was for opening the door near the blower to recirculate interior air, and since another one of them had 3 positions and moved in the mix setting, I believe it was for the defroster setting. the 3rd one was in the dead center of the car and I was unable to determine it's function, though it appears to move correctly.

Does anyone know how many of these doors and vacuum canisters there are (I've got A/C but no ACT) in this system, and their general locations? I'm pretty sure this whole problem is the vent blend door not closing, but I can't find a canister that seems to affect vent flow when it moves.