vacuum not switching at dash buttons

The main thing with the AC was an added electrical switch for applying power to the clutch. First crawl under there and look at the hoses and make sure they are firmly attached to the back of the switch. Then pull the switch assy and see if it is actually moving the shuttle in the back when you push various button. This moves the vacuum routing as well making electrical connections. Look at the sticky at the top of this sub-forum for good info on how this work.