89 ac problem

my ac on my 1989 country squire ( crown vix wagon) works at a stand still. When there is a load placed on the engine, the temps gets hot and coms out on the floor and defrost. I replaced the auto temp vaccuum swith last year. It seems to be working. I was wondering where the main vaccuum comes from for all the va. switch this car uses.

Thanks,

John

its is the vaccum canister, which is on the right side inner fender well, it is black and it looks like a coffee can. I bought one for my CV cost me about $29.00. there are two styles a big one and a little one that looks like a tomato can. The big on is for cars with electronic climate control and the little one is for standard climate control. If you want to test it take the can off (two 8mm nuts) wrap it in duct tape, then with saran wrap and then again with duct tape and re install the problem should have gone away a little unless the can is rotted badly