Trailer Lights Problem

I had working trailer lights on my 2007 taco- installed kit when it was new. Last month they stopped working correctly. The running lights work. The left and right signals work. However, when I step on the brakes, the left brake light/signal flashes. ??????? The signals/brakes on the truck work normally even thought the left trailer stop light is flashing.

Any thoughts greatly appreciated.

 

test the guilty socket and see if the power is flashing.

If no, the bulb must be the issue.

If yes, then start working upstream till you find where you have constant voltage.

 

I forgot to add that if I have the running lights turned on, the brakes work properly. For now I am running with the lights on when the trailer is attached, but I would like to get the problem solved. They problem occurs with new magnetic lights and new led light kit.

Could there be something going on with the flasher unit?

 

I would reseat the bulbs in the trailer lights. Sounds like a back feed problem.

Can you try a different trailer? If another trailer works fine, then the problem is definitely with the trailer system. The trailer system is the simpler of the 2 and easier to diagnose.

Electrical is always the weakest link. Start with simple things like bulbs and the trailer plug.

 

Problem could be anywhere with any bit. But you either start at the end and work upstream (easiest normally) or start 'somewhere', like a connection point, and either work up or downstream, depending on what you find at that point.

People guessing on an internet could get you the right answer. Or not.

Testing definitely will find your issue.

 

I have the same problem with two new sets of lights; one of which is sealed led bulbs. I guess I will start with the traler connector plug on the truck (I put a new plug on) and work back towards the truck bulbs.

thanks for the help!

 

I had the exact same symptoms, tried messing around with the trailer ground, truck ground, etc nothing fixed it. Having truck lights on yielded different results from no truck lights. I had an aftermarket kit installed too with one of these little adapter things and it turns out that was the problem. Cut it out, soldered a new one in and it worked. If replacing the trailer connector plug doesn't work and your fuses and bulbs are good I'd look into this. Mine was in the bumper ziptied beside the hitch. It converted the 5 wires to 4, not sure if you have a similar setup.

 

Could be the LED's - some vehicles have trouble because there is not enough current "load" from LED lights.
Google flashing led trailer lights.

 

Check the trailer fuses first. There's a couple that control the trailer lights.

 

This turned out to be my problem. Replaced and all is fine.