Need a vacuum diagram (92 DOHC)

[Kalgorn]

My HVAC controls don't work in my 1992 Lumina Z34. Cruise doesn't work either. I've owned the car for over a year and I don't believe they've ever worked. I want AC though... can't stand this heat anymore. I was checking the vacuum lines around my cruise control module and found the culprit. Top soft line is corroded and cracked and very brittle to the touch. However, the bigger problem lies in the small hard line on the bottom. The line goes down to a T. One side goes somewhere (not sure yet) and the other side is just... gone. Non-existent. No clue where it's supposed to run or what happened to it.

Can someone provide me with some sort of vacuum diagram from a service manual? I emailed Chevy about it and they said to either check a dealer or pay $105 for a service manual. I'm going to go to a couple dealers tomorrow on my way to school to see what I can get my hands on.

Any help is appreciated.

[series8217]

Here's a diagram I colored.
You can see the line from the cruise control also goes to HVAC! Your vacuum servo for the heater/AC controls is probably not getting vacuum.

[Kalgorn]

Sweet! It's a little confusing at first glance but I'll figure it out.

[Anonymous]

Here is one, a little worse, that I made a few months ago, hope it helps.

You know what? Looking closer at your diagram, it is incorrect. The line from the front valve cover T-s with the line from the back valve cover, then this line goes to the airbox. The PCV line is the one that comes from below the lower intake manifold, in the center, and goes right behind the throttle body. Notice mine, it is correct. Just trying to help!

[series8217]

triple post!

[series8217]

triple post!

[series8217]

It works the same either way.
I don't think there is enough vacuum at WOT to make any difference for oil drainback at high rpms whether or not you pull vacuum through the at the crankcase vent or a valve cover, though I guess its something to think about.

[Anonymous]

I'm guessing the reason behind it is for part or closed throttle, where vacuum is high, so that there is not much of a pull on the breather assembly, but is still adaquate vacuum for the PCV system.

[dohcfiend]

most wbodies have the vac diagram on the top of the upper rad support