Even though I pretty much had the ATC repaired enough to pass safety, there was one nagging issue. There never seemed to be enough vacuum present at the Master Switch to turn the system on. I had planned to bypass this because the only effect seemed to be that the blower would never turn off but would rather stay on low when you shut off the system. Well, I got playing with it again tonight and I noticed the little valve that is mounted near the Fresh Air/Recirulated Air mode door. This is on the extreme right end of the ATC unit. I noticed that the valve plunger wasn't springing up the way it should. Fortunately, I had two spares :-) I simply changed the valve and the ATC now works perfectly! The refrigerant is low so there is no cooling but that was expected. http://www.nybclub.org/membercars/bradhogg/76NYB/atc.htm