Re: TJ: wire in back of enine compartment not used
Not sure what you are looking at. My 2000 TJ has a small connector with two blue wires--maybe 18-22 gauge, plugged into the top of the AC can. This allows the AC to shut down if the system is empty, saving the system from damage. This is on the passenger side, and is about 5/8" across. I have only one other connector, mounted to the center of the fire-wall, about two inches wide. This is part of the main wiring harness.
Right Wrongs Nobody