Hello Everyone,
I have combed through the posts on this issue and did not find any answers. I have a 2012 Jk with factory hitch. When I hook up the trailer lights I get hyper flash on dash and warning saying right rear turn and brake lamp out. The lights work for a second before the computer kicks this warning and disables power to the right rear. I changed the harness for the trailer on the Jeep and it did not help. As soon as I disconnect the trailer from the harness, the hyper flash and warning goes away and the blinker and brake light work properly. The trailer is less than a month old and all bulbs working fine. I am about to drive across the country so any help on this issue would be greatly appreciated. Thanks,
James

 

Just a few background questions. Have you towed this trailer with the jeep before with no issues and this has just started? Is this a manufactured trailer? New or old? Have you towed anything else with the jeep with no issues? Can't say that is the case here, but I've just seen plenty of inexplicable things when there is a bad ground. You don't by chance have another vehicle you can plug the trailer wiring into just to confirm if this is a jeep issue or a trailer side issue?

 

Yes I have towed with the Jeep before without issue. I went on and hour ride yesterday with this exact trailer without issue. The issue started today. The trailer is manufactured and less than a month old. I do not have another vehicle but I might be able to try a different trailer tomorrow. I will try to check the grounds on trailer lights, but it is already loaded and most of the wiring is behind the wood walls. Might add extra grounds to just make sure. Thank you for the response.

 

Sounds like a trailer issue more than a Jeep issue. Lucky for you that trailer wire troubleshooting is super easy compared to Jeep wire troubleshooting. I’m assuming it’s a simple 4 pin harness? If you have a multimeter, check continuity between the ground and the 3 how wires for each light on the trailer harness. My bet is that somewhere between yesterday and today, you burnt a bulb, snagged a wire in the trailer, or have a loose connection. If you get good continuity on the ground and all hot pins, check the security of the pins on the plug for both the trailer and the Jeep.

I would typically do a resistance check on a wire harness vs continuity since if you have high resistance, that could indicate a partially broken wire. But for you I’m only suggesting a continuity check since I know nothing about your trailer or wiring harness.