I'm working on my heater AC system. Started with the vacuum and controls before I let the AC guys fix the AC. By the way I get to stay with R12 as I purchase a dozen cans the week before they stopped selling it.
My problem is the white vacuum switch that is up under the dash on the heater box. The one that controls the vacuum to the Water Shut off Valve in the engine compartment is leaking vacuum like a sieve.
I have 12 inches of vacuum from the engine and after isolating everything but that switch and taking a reading on the hose going to the Hot water shut off valve get only 2 inches of vacuum.
Try as hard as I can I cannot seem to find anyone that has that switch. They must be calling it something else. What would you call it? I would like to purchase a new one if possible. I know I can get a used one locally but I would rather have new.
HVAC vacuum diagram(large image modified to link-aapple)
|UPDATED|4/22/2013 9:43:01 AM (AZT)|/UPDATED|