Front vents of A/C not working

I have a 95 z28 and the air only blows through the top and bottom vents, but not through the front... the air is cold just not blowing out the four front vents. anyone know what this could be?

http://shbox.com/1/vac_check_valve.jpg

Check this valve.... Passenger side by fire wall... Pic courtesy of Shoebox..:)

what exactly would i be checking it for...?

Make sure they're all connected and not brittle causing a vacuum leak.

http://shbox.com/1/4th_gen_tech2.html#HVAC_vacuum

if its not a vaccum leak then what else could it be

if its not a vaccum leak then what else could it be

Is that a hypothetical question or have you proved you are getting good vacuum to the mode selector?

i have checked it and its not a vaccum leak