Cadillac Repair: 1994 cad a/c, court qualified ignition expert, www.autotheftexpert.com

Question
Air conditioner on my 1994 Cadillac Sedan d Ville works fine - but
air does not always come out vents  doors/flaps that direct air to vents "close"  air is blowing behind the dash   then with no apparent change of circumstances the air will suddenly be directed to the vents again  I have replace the programer twice with used ones as new cost is prohibitive  there is vacuum to the programer
any ideas as to where to look next   Thanks

Answer
Hello,

You are on the right track with the vacuum. I would be seeing if I could rent a vacuum pump at a parts store. Start checking doors by applying vacuum to them. See if you have a door sticking or binding or if there is a line problem.
You state circumstances do not change, but you did not say if driving or sitting.

http://www.autotheftexpert.com