I have a 2004 TJ but figured I would post this here to get more opinions.
I hooked up the trailer I have (new wiring on it with no issues) to my TJ. It had a wiring harness already but it looked old.
BEFORE I hooked it up, all electric items worked fine.
After hooking it up we had gremilns appear
what its doing now:
-when I hit the brake pedal the lights (in and out) turn on (funny but annoying)
-the right turn signal turns on a form of the hazards (right signal is brighter then the left but both flash)
-when headlights are on the right signal doesn't work
-left signal is fine.
I guess that hooking up the trailer, ie using the sketch harness, made some sort of short. The ground looks good.
I was thinking about just pulling the whole harness that is spliced in but figured I would ask for some advice before hand...