A/c Problems (94 Camaro)

[HaaHa]

Im looking for some suggestions on why my a/c doesn't blow out of the front vents on my 94 camaro?? I seems to work on all of the a/c settings hi/low etc... but only blows out of the floor vents and the defrost vent... I can't seem to visibly see any cacked or broken vaccume lines. Is there a common issue with this type of thing or any suggestions of what to look for or where to start? Any help and input would be greatly appreciated.

Thanks in advance

[5.0THIS]

Seems like the blend doors are stuck, or the system that controls them (I believe it is vacuum controlled) isnt working.

[HaaHa]

I thought the same thing, but have pulled the dash apart and traced all of the lines... There arent any visible problems that I can see. The blendoor works great too. Im at as loss really, I cant understand why it wont blow out of the vents...

[jloshotz]

Under the hood near where the a/c lines go into the evap at the firewall is a small plastic check valve, which I can practically guarantee is broken....about a five dollar fix. Give it a look see