[jeffcoslacker]

Originally Posted by tblake

wow, hmmm, now that you say that, I'm gonna go play. If you figure out anything else let me know. Sorry to get off thread here, but whats wrond when the air (wheather is be heat, ac, bi-level, or just vent) blows only out the defrost, and never moves. It does change to ac or heat or vent or whatever, but only blows out the defrost, and slightly out the floor, and even a little less out the dash vents. I thought it could maybe be a vacuum leak, since some cars use vacuum to controll this, right? But I know its controlled electronically. Whats is the first thing to check out, what could be the cause of such a situation. And by the way, sorry I know I know, lumina thread, but this vehicle is a 1995 GMC jimmy sle with the 4.3 v6 VinW . Thank you.

Like I said, the ones that came out in the mid 90's and up weren't having problems like that yet when I stopped working in the shop, so they could have a nuclear reactor in the dash that operates the blend door for all I know.

But that sure sounds like a vacuum line leaking, you're right. Did you check the ball and see if it's cracked?