I found the vacuum lines located in the back of the engine compartment, along the top. The line is a very skinny hose (pencil lead size) with attachments along the way. In tracing the line, I discovered that on the passenger side, what appears to be the "end of the line" was just hanging there, not attached to anything. After combing the area and not finding any open ports and the fact that the rubber end was split, I concluded that the line was just "attached" to a protruding bolt--something to stop the air leak. So, I experimented.
I put a screw in the open end and whadda-know, the A/C worked, AND the engine ran better. To insure it wasn't a fluke, I would turn off the AC, remove the screw...turn it on--nothing....reinsert the screw, turn it on--it worked........did this several times.
I taped the screw tightly into the end with electrician's tape and all is working fine.
This may not be correct, and it may be the 'redneck' way of doing it, but every time the local Jeep dealer replaced these hoses and re-attached it, it cost me $100. AND it works.