A/C blows out defrost only...HELP PLEASE!!!

[rockinrobin]

Hi !everyone!
My A/C blows ice cold, but it just started blowing out of the defrost instead of the panel...sometimes it's a mixture of both, but mostly the defrost. Sometimes it doesn't blow at all when I get on the gas...? Is there something under the dash or hood that controls the vents to the A/C?? What can I do about this and how do I fix it?? Help please!!!!

 

[Kilgore Trout]

Vacuum control line in dash is leaking. Failsafe mode is defrost only. Find the leak and correct.

 

[wmburns]

+1 on above. Look for a break in the vacuum line in the engine bay and the firewall.

If you can't find a break in the vacuum line, the problem is in the dash control or vacuum lines behind the dash.