vacuum hose for vents and defroster

[bryan76]

i got a non ac cab but done cut the firewall for this have all the stuff from a burb for under dash etc all i want is the heat and vents and defroster to work all the lines are hooked up to actuators the main source from engine the line was melted can i just hook up to a vacuum source from intake to the source line then to ac controller thanks
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[hrc200x]

The ones I've seen attach to a vacuume fitting on the top of the intake behind the carb. Somtimes the one fitting in the intake has 2 or 3 different spots for different vac. functions or the main line has a "T" in it. There should be a vacuum line supplying vac to the controler, some trucks also had a round vacuum resivour. I think I've seen them mounted either above the heater core on the outside of the cab, or over by the fuse box on the outside of the cab.

[donut]

In short, yes.
There is supposed to be a vacuum res (ball), but mine broke, so running off straight manifold vacuum now. There is what appears to be a check valve? cut into the factory line. function would have to be investigated.

[chengny]

These might help:






The check valve is to prevent loss of vacuum (used to position the HVAC dampers) during times of low intake manifold pressure - i.e. at WOT.