Seems to be a common problem, I was only getting air through the defrost and floor, no vents. Lowered my glove box to gain access to the multi colored vacuum lines. They run down from the upper passenger side, and junction into a clear rubber looking connector. Not sure what this part is called, maybe a vacuum junction? Anyway, it just snaps together, I took it apart and the nipple where the pink hose connects was plugged. Thats your vacuum. Just took the end of a paper clip and cleaned it out. They work great now. Maybe this will help someone, i've seen a few posts on the subject lately.