I have a 1996 s420. Purchased two weeks ago. The guy I bought from said there was a problem with the AC. It would only blow out of the defrost vents. I found a vacuum line disconnected and got some of the vents working, but they seemed sporadic. I began to track down vacuum lines using AllData diagrams. I located what AllDate describes as the vacuum block. Seems like a manifold to distribute vacuum to climate control and other areas. I moved the climate control to another outlet on the block and all the vents began to work properly.
Can anyone explain this "vacuum block". Are the outlets all the same or are they somehow calibrated for particular duties. Only three outlets are being used. There are four empties.