Diagnosing Intermittent Trailer Wiring Taillight Functions on Trailer Towed by a 2000 Jeep Wrangler

Updated 05/29/2014 | Published 05/28/2014

Question:

Have recently installed a curt 55354 in a 2000 jeep and have attempted to hook it to a utility trailer with Y type 4 wire plug with two brown wires wiring. The power at the vehicle plug for all lights checks out correctly with a LED circuit tester. The parking lights on the trailer typically come on just fine, but the turn and brake lights on the trailer very seldom come on. Typically they dont work at all, but if I leave the brakes on or turn signal remove a bulb from the tail light, remove it and try to put it in backwards the element will light or flash dimly. I then immediately put the bulb back in correctly and the light brake or turn works just fine. That makes me happy, but if I turn off the turn signal or take foot off brake and flick the signal or step on brake the light does not come on. Occasionally I can get he brake of turn signal lights to work if I unplug the trailer from the vehicle and plug it back in. However, that is very intermittent. Any words of wisdom?

asked by: Morley

Expert Reply:

It sounds like your trailer does not have sufficient grounds.

The white wire coming from the trailer connector needs to be securely grounded to clean metal on the trailer frame. One other place to check is the mounting points for each of the lamps on the trailer. They receive their ground connection from their physical attachment to the trailer frame. If these connection points are not tight or if they are corroded, you will not get good ground continuity which would certainly cause the problems you describe.

I attached an FAQ article on troubleshooting 4-way installs for you to check out as well.

expert reply by: Jameson C