Controlling Heat

[polkayoureyeout]

I've cross-posted this on the 7.3 IDI forum.

This is my SPECIFIC problem; there is a vacuum-servo valve that cuts OFF the coolant flow to the rear (auxillary) heater core. I can't find what ACTUATES that valve.

I think its been bypassed and removed in my van, there is a brass "elbow" linking two vacuum lines together up behind the heat/ac control module. One vacuum line (small colored plastic) goes to the cutoff valve, the other (thicker black rubber) goes into the engine compartment and then to nowhere.

I can't figure where it was originally supposed to go, and I can't figure what the "missing" part is, and how it was actuated from the controller levers.

I've closed the valve with a zip-tie which allows the AC core to cool the rear air (the heater always won) which I will clip in cold weather. However, I would fix this thing if I could figure it out.

Plus my cruise doesn't work in a halfjacked way (will keep a low speed, but not a high speed, like it can't get enough vacuum to pull the cable hard enough), which I suspect is a vacuum leak, not a totally broken thing. Maybe this hose goes in a port I can't find, or something.

Any clues are welcomed.

zac

[FULLAUTO]

sounds like you could use a new vaccum pump for starters , Wade