dieselenthusiast wrote:
Okay, I read this thread and I’m still a little confused. I’m about to order the factory wiring harness for my Gasser KJ so I can tow my camper. So what’s the problem with the factory writing harness? Maybe the fact that the harness doesn't work with the trailer brakes? The mopar harness (RV 7-way connector) should be designed to plug into the factory wiring (through the taillights), so I’m not sure why you guys are talking about extra wires, etc.
The "factory trailer wiring harness" your about to order is not the same as a "factory
installed harness"

The harness connects in the rear right quarter panel and unless you have the EVIC all signals and wiring are NOT present in the rear quarter panel to operate the included relays.

It is not complete
This requires a "supplemental" harness that's a rather half a** arangment. It does not disconnect the trailer battery when the ignition is off for one thing. This will allow any load from the trailer to run down the starting battery in the jeep. Additionally KJ's, at leat my 06 crd, are already partially set up for towing even if you do need the supplemental harness and the supplemental harness
does not use what's already there. I think what your reading here is people using the supplemental harness but incorporating what's already in dash area of the KJ, that's what I did. Trailer tail lights do not run directly off the onboard lighting system. They are operated by relays and those relays need a power lead that's not there. If you try to install using the wiring diagrams in the FSM you will be driven to drink or go insane
I hope this clears it up for you but know first hand it can confuse you more
