Cadillac Repair: Air condition, vacuum line, vacuum hose

Question
I have 1991 cadillac deville and the a/c does not blow out the front vents.  Could there be a loose vacuum hose.  If so where would I start to look for a loose hose.  Thanks...

Answer
Could be:

Loose or split vacuum line going to the center vacuum diaphram.

An inoperative center vacuum diaphram.

A faulty Ac/heater programmer.

I can provide PICTURES and directives on testing the system if you e-mail me at: onlineautohelp@msn.com