hey, does anyone know anything about the 2001 astro passenger van (LS 4.3 AWL) air vent system? a shuttle driver of an astro van told me to turn on DEFROST at HIGH setting to recirculate interior air (without drawing in outside air). then, i was unable to get any dash vents or other vents to work! even air conditioning would only blow onto windshield! no matter what variations done of the control panel dial, only air blows on windshield through the windshield vents! is this a fuse?
i heard the sound of a baffle or vaneaudibly turning/closing upon running defrost at HIGH. did some directional baffle/vane close or otherwise reposition, not allowing air to resume its normal pathway?
opinions are welcome, since i am about to take it to my local mechanic, and he initially did not know the answer to this strange occurrence.
thanks, SDCA_Paul

 

sounds like the vacuum source for the hvac system is either broken, leaking, or has come unplugged. With out vacuum, the system default to the windshield so you can still see while your driving

 

hi, shawnvw: yes, i think you're correct, and i took it in to a reputable mechanic yesterday. today, they called me confirming what you suggest and what i had researched a few days ago. and i do really appreciate your confimation of this! have a great day!

 

Bringing back an old thread here but..

I have the same problem. The air only blows onto the windshield and to the floor no matter which setting I set the air conditioner (a/c) to.

I want to diagnose this and fix it myself. Where is the first place I should check to see if a vacuum hose has come undone?

 

NVM! I just fixed it! Wow this forum IS useful lol

It was a broken vacuum hose underneath the throttle body. I hooked it up with the corresponding tube and it worked.