It sounds like you have left off or damaged/pinched your vacuum harness to the hvac control head. Check and make sure you have solid connections...it could also be that you twisted the box when you pryed it off of the firewall and broke the defroster valve (the little door inside the case).

 

It just so happens that I have the same problem right now. The air blows good through the vents but hardly at all from the defroster or the floor.
I found that this mode control unit seems to be weak 'cause if I assist it to full travel then I have full air flow.
This is on the drivers' side.

[IMG]local://upfiles/2910/67D1EE06003D4B27AF24C81C7DC89C8C.jpg[/IMG]

 

thanks chevy lover but there is one thing that i dont undertsan about that is that when i turn the **** to chang the mode it doesnt like click anymore its werid

 

Click? Where was it clicking before, at the switch?

 

like when you turn the know to put the air at your feet it would click it to place when you turned it

 

Hmmm, check the switch....

 

i already did like evrything else works but the mode **** i tryed everything i could think of

 

Hmmmmmmmmmm thats weird

 

yeah, and everything is put back together right