Heater controls/Vacuum lines

[Lamardoo10]

Back in Nov '15 I bought an 86 K5. The PO had put a rebuilt 350 in it. It runs fine, so far, fingers crossed.
There are a few issues though. 1 is the selector for the heater/AC selector, the one that says; heater, vent, ac, off, etc. I think the PO didn't hook the vacuum line for this back up. My problem is, I don't know where the attachment point is in the engine compartment.
So, where should it be, what do it look like?
Btw, although I fix things for a living, I'm not a car mechanic.
Thanks.

 

[cwn anwyn]

I can't remember but on my 84 the heater vacuum hose comes out of the firewall in the grommet above the passenger side valve cover or the same grommet that the heater wiring/AC wiring runs out of. Its a small black almost plastic line that looks like a thick wire, but it has a hose end on it. I run it to the vacuum port between the carb and distributor on the manifold.

 

[4xfrankie]

So, you don't have heat/ac and you think it might be because this vacuum line is loose?