What the heck does that go to? I'm going to guess something not important? :p

 

It provides vacuum to the heater and a/c position control. Without it installed the controls will default to the floor and the windshield.

 

I put a one way valve in line of mine and left it plugged in stock location, that way it won't see boost. Now i'm wondering if while i'm in boost and it isn't seeing vacuum, will the vents switch over to windshield and feet? Or is vacuum only used while switching vent positions?

not a big deal just curious.

 

The vents will stay in the same position unless you removed the vacuum tank from under the passenger side frame rail (small black tank about 8 inches long)

 

Awesome, I'll put in a check valve, but I think I might blow that line out with boost, I guess we'll wait and see. My next question was going to be "what the heck is that thing on the passenger frame rail"... haha.