Question on the vacuum line for the hvac controls

[boyer61]

I got an 84 k10 305, edlebrock intake and edlebrock carb.

The PO cut the vacuum line for the controls that divert the heat in the cab, where can i hook it up to?

[trickedout420]

any source of vaccum, run a line to the engine

[ryan_thompson87]

No, it has to go to the vacuum canister on the firewall (Orb on the firewall, sorta Death Star looking thing), so it has reserve vacuum, and there is also a vacuum delay inline. If you hooked it straight to manifold vacuum the heater would kick to defrost everytime you went WOT. (No vacuum)

[boyer61]

Any idea on how it hooks up? there are only 2 lines connected to that canister, they look like they are going to the tank.

I hooked it up to the manifold, it's delayed a good bit, but it works.

Another thing, i had hooked it up at work, on the way home it nearly died. When i was turning into my drive, 90* going about 15MPH, it died and it was a pain to start back up, acted like it as flooded. Could that be related?

[ryan_thompson87]

Your thinking of the EVAP canister. The vacuum canister looks like this: http://www.google.ca/imgres?q=GM+vacuum+canister&um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&tbm=isch&tbnid=4G8o4PGLnailrM:&imgrefurl=http://www.ecklerschevelle.com/chevelle-air-conditioning-vacuum-canister-1968-1983.html&docid=hPirPaYa8kF6nM&w=265&h=265&ei=uDZGTrbeEIW1sQKE__X5AQ&zoom=1&iact=rc&dur=305&page=1&tbnh=138&tbnw=159&start=0&ndsp=44&ved=1t:429,r:30,s:0&tx=61&ty=62&biw=1680&bih=862

[boyer61]

Ok, i seen it now. Only thing is, there is one line going out of it, then it T's off, where do the lines go to? They are cut as well.

[ryan_thompson87]

Not sure you'll have to find a diagram.

[boyer61]

Anyone else have any idea of where it hooks up?

I just tried to hook it up inline with the brake booster vacuum, and it didnt work at all. I had no brakes. I made sure it was all sealed as well..

[Prong]

I run mine off a T fitting from the vacuum line for the transmission modulator. Has worked fine for years.

[boyer61]

would that work with a 4 speed manual?

[96K2500]

would that work with a 4 speed manual?

No, you won't have a modulator valve. You should have a vacuum port in the manifold behind the carb or you have a full vacuum port on the front of you carb.

[boyer61]

Ok, I ll try to run it again through the brake booster vacuum line.

[lmbull]

boyer61 did you get this problem resolved? What is the PO? I have a 84 I just bought and the heat selector doesn't work. No matter what setting it's on it blow out the vents on the front of the dash. I can't figure out where the vacuum source to the selector comes from.

[boyer61]

There was a small black plastic hose to the right of the heaterbox on the firewall. I just connected that to a vacuum port on my carb.