Trying to figure out a vacumn problem with the climate control on a 92 Loyale. Where does the vacumn line go that enters the firewall on the Drivers side? I show 18 lbs on the other side of the canister on the passenger side so I'm going backwards until I find the problem. My guess is that the line goes to the selector switches for the climate control. The air will blow through the dash vents but no floor heat or defrost. I see that the A/C compressor runs on heat because the switch engages when the vacumn servo engages to run heat to the floor. That much I figured out. Has anybody had the climate control assembly with the pushbuttons go bad? Any suggestions would be appreciated.

generally in my expierence, they don't go "bad" - the hose that supplies the vacuum to the control gets accidentally disconnected, either on the dash end, or the underhood end - you will probably hear a vacuum hiss when this happens, and the A/C system gets stuck as you describe

 

if you have a manual with diagrams as to how it goes together (IE FSM, Haynes, Chilton), the dash control is actually really easy to access and examine

 

good luck

The Chilton manual is a 300 page paperweight. No diagrams of the vacumn system other than emissions.