Does Trailer Wiring Harness have to Connect to Battery on a 2018 Jeep JL Wrangler

Updated 08/07/2018 | Published 08/06/2018

Question:

I dont pull a trailer that often. I do have a 12V power source with 15A fuse protection standard cig. lighter socket in the rear at the tailgate. Would this be adequate power for the occasional tow as opposed to a hard-wired 12V source all the way from the battery? It would seem to me to be much easier for low-amp applications.

asked by: Bill M

Expert Reply:

There are several reasons why the power wire has to connect directly to the vehicle battery when installing trailer wiring harness # 118786 on your 2018 Jeep JL Wrangler.

First, the 12 volt accessory circuit was not designed to support the additional power draw of the trailer wiring harness. A wiring harness must have its own dedicated fused connection to the battery.

Second, attaching the power wire to the battery maintains the level of separation between the vehicle wiring and the harness wiring. We have seen cases where customers have used a 12 volt accessory circuit and the harness failed. We have also seen cases where the accessory circuit on the vehicle failed too.

Third, since this installation deviates from the instructions it will void the trailer wiring harness warranty.

Routing the power wire to the battery just takes some time and you will avoid all of the issues mentioned above. To help I have linked a help article with tips on routing the power wire.

expert reply by: Michael H