My 1994 Z28 has lost its vacuum to the AC/heater/defroster blower control. I haven't been able to find the leak. No lines appear to be broken or loose but I am not really familiar with how it comes off of the manifold. I was wondering if there is a good source for a diagram on how the vacuum lines are routed? And where is a common location for this type of problem to occur?
I have checked under the dash. But I'm guessing the problem is under the hood.

 

A Simple Way To Find The Leak Is To Disconnect The Vacuum Lines One At A Time From The Manfold Tree. If The Idle Doesn't Change On One Trace That One Down. It's Probably The One With The Leak. Sick

 

The leak turned out to be in a 3 way vacuum line connector next to the PCM before the line goes through the firewall. The cracks were so small that I missed them at first, but were visible when I threw on the "cheaters". I temporarily fixed the problem with silicone. I haven't been able to find that connector on line, so will be going to the dealer soon. And there is a vacuum line diagram on the spec sticker next to the radiator.