I believe I have a had ground somewhere between my post cat o2 and the computer. I've come to this conclusion cause it's not showing up at all on a live scan at a shop, along with that, my part time light is coming on from the sensor on top of the t case and the two are close and wires are bunched together and run up above the tranny and into the engine. My question to all of you fellow jeep enthusiasts is: where would the ground for these be found? Ive looked, and can't find anything! Schematic says there's a ground.

96 xj 4.0 4x4 automatic w/ AC

Any help is greatly appreciated! Thanks guys!