Climate Control Hell

Following Churchill's advice Well, I finally made it all the way through Climate Control Hell after realizing that I was halfway through. In case you're wondering, the vent selector was not working properly. They are controlled/powered through the vacuum of the engine's intake manifold. It was a hard problem to source due to a number of factors. Being that I've never experienced this problem before, the sourcing of a vacuum leak can be difficult, and it was hard to find a proper diagram of the engine's vacuum hoses, I'd say that I'm doing okay with it. I tried a number of things to help in this regard, including the purchasing of: Purchasing a new vacuum reservoir ball. a 3-way check valve that was missing. a new vacuum selector that was part of the climate control selector. various vacuum hoses a Chilton's book for the van a Chevy service manual for the van (online). I initially had tried the new vacuum hoses, reservoir, check valve, ...