Hey guys,Replaced the ground cable yesterday.The one from the neg. post to the engine block(1990 MJ 4.0).While there I cleaned up the grounds and put it back together.Got in this morning and the oil gauge is pegged.Popped the hood and I had unplugged the sending unit when I did the cable.Plugged it back in and I'm still pegged.First question: with the key on the sending unit wire that plugs in the rear of the unit should be hot right? It is not hot,all gauges work except oil.What do ya'll think could have happened? Only thing I did was the ground cable that's it. Everything worked fine before I changed the ground,I did drive to to the Ace hardware unplugged,but that shouldn't make any difference,should it? I'm mystified in Texas.