tombodad

Hey guys
So my defrost works fine, and my fan works, but only on the floor and defrost modes. My a/c gets cold, but only blows on the floor. No matter which setting I put it on, no air will come out of the vents on the dash on each side and in the middle above the stereo. Anyone have any clue whats going on here? I really dont want to pull off the dashboard....
Thanks

Z28SORR

Your HVAC system is on the pass. side under the dash. There are several flapper that control where the air is directed. They may be stuck or they may not be getting the signal from the HVAC controls. You need to get behind the dash and check this stuff.

Silver

I had this same problem and a dude told me exactly what was wrong with my car. Under the hood on the pass side up near the firewall is a few small black rubber hoses that all come together into this little round black plastic splitter thingy. It was dry rotted and cracked and wouldn't hold a vacuum so the system wouldn't switch to vents.

I got the part at AutoZone... I think most the GM's use the same one.

Joe Bellman

This is your most likely culprit
http://shbox.com/1/vac_check_valve.jpg Check it for cracks.
or
http://shbox.com/1/vacuum_tank.jpg
The line that runs between the tank and valve may have cracked or broke.
If this is broken, don't waste time looking at the local parts stores, you won't find it. I tried 5 in my area before I went to the dealer. Tell them to order part number: 12124134 BTW, this is correct part number for '93-96 cars.

Now send a email to shoebox and say thank you.
http://shbox.com/1/4th_gen_tech1.html