[jsherm007]

So I picked up a trailer and my friend dropped it off with his F-250, lights worked. I have a JKU with the factory harness and plugged it in and nothing happens!

I checked fuse M17 as another thread said that was for towing. Last time I used the harness was last year. Since then I've done a few things to the jeep but nothing that should have caused a problem with this wiring.

Any ideas what this could be a result of? I followed wire up behind the tail light and there doesn't appear to be anything loose.

The worst thing I saw was the brown/tail lights plug (from jeep) seemed darker inside at bottom than the yellow or green. But I used the end of the trailers 4-way plug (green) and stuck it down in there and moved it around. I just got some connector grease out.

Absolutely nothing seems wrong in my wiring but clearly something is.

 

[JKSurf]

My boat trailer lights are real temperamental, sometimes they work, sometimes the don't. First thing I would do would be to use a multimeter or tester to make sure you have power at the plug.

If the plug is getting power I'd clean the plug and trailer connectors. Rolling up a little sandpaper and using it in 4 pin connector usually does the trick if I haven't used it in a while. I'd also check to make sure your trailer lights have a good clean ground. I have to unbolt my ground wire and sand it down every now and then. I assume you're near the water so that salty environment is always messing with my trailer lights.

 

[tarpon4me]

Is your hitch ball really rusty or corroded?

 

[teXan]

Check the ground and make sure it is good. Also like mentioned above a really rusty ball can cause ground issues for the lights on the trailer.

 

[jsherm007]

Found my problem! When I installed the LED taillights I plugged the taillight into the socket for the towing wiring harness and the towing wiring harness into the socket for the taillight! The taillight worked fine so I never knew there was a problem. Thanks all for the responses! I feel like a dumbass!

 

[Longtallsally]

Found my problem! When I installed the LED taillights I plugged the taillight into the socket for the towing wiring harness and the towing wiring harness into the socket for the taillight! The taillight worked fine so I never knew there was a problem. Thanks all for the responses! I feel like a dumbass!

Don't. When I added 7 pin for trailer brakes to mine, I made the same mistake, a few times...