There is a heck valve under the hood that is there to prevent boost from damaging the heater vent controls. Check and see that it is not popped. If it is, then you probably popped one of the diaphragms that operates the vents. My guess would be that it is the one near the floor just to the left of where the heat comes out onto the floor. That is where my popped one is. I tried getting one from the dealer, and have been waiting a couple of months for it. They charged my card, and now they've changed hands. I wonder if I'll ever get my part or money back. Anyways, pull the vacuum line off and check to see that it holds vacuum. If not, then you have found your problem. If it does, then as mentioned earlier, it could be the selector. Good Luck, and let us know how it turns out.