Good morning Volks, once again i need to tap this well of knowledge.  I am in the proces of replacing fuel lines (thank you for all your help on that as well) and have removed all of the intake "spider" plumbing.
I will try and describe what i am looking at and where it is located on the vehicle - i am hoping someone can tell me what it is and what it does.
It is located (and joins 2 rubber hoses) on top of the engine, just beneath the idle stabilizer control valve and slightly to the right. Connects from the cylindrical black tower (about 8" high and 4"diameter) located on top of engine at rear where the cases join, and runs to the intake plenum.
The switch itself is just a hollow plastic cylinder about 3 to 4" long with a portion of its inner wall lined with copper.  There is a electrical connection on this item as well.  The hoses connect at either end of this item and seem to be rotted, in fact the portion closer to the "black tower" is collapsed/crushed to less than 1/4 of it's inteded size.  The hose with switch is used to recirculate crankcase fumes back to the intake and combustion chambers.
What does this item do??
Forgive my rambling above - as i read it i wonder how you folks will be able to understand all the mumble jumble.
thanks very much.
87  Vanagon GL  7 pass - 2.1
90  Jetta  TD