Constant 12v at my harness all of a sudden

Hello,

I just got a utility trailer, everything worked fine when I picked it up. Now two days along I plugged in and the trailer brake lights were on and the blinkers would not work.

So far I have found that I am getting a constant 12v at both the right turn/stop and left turn/stop pins. And when I pull the fuse from the fuse box the voltage goes away.

This is my first experience with a trailer and wiring, what the next trouble shooting steps? Thank you in advance. (2016 Tacoma SR5 with factory tow package)

 

If you're still within warranty I'd just take it back and let Toyota deal with it.

 

Not under warranty and I live far from dealerships

 

Bad grounds. Corroded connections. 99% of trailer lights problems.

 

It’s doubtful the problem is with your truck. It is likely the trailer wiring. Since all was working well initially sounds like a wire pulled lose or is being shorted somewhere. You need to trace all wires from the front plug back to the lights. Inspect every inch of the wires and pay extra attention to the connections. Could even be the front trailer plug itself.

 

Corrosion or grounding on the trailer is the most likely culplret.

 

It’s my truck, because I had two neighbors connect just to check and everything works fine on the other trucks. With truck off I got voltage through the Fuse trailer brake controller pin as in the attached picture-that’s the harness where the brake controller plugs into.

 

Anyone point me to a diagram of this plug

 

Well, took it to Toyota and come to find out it is "the combo meter" and apparently that involves replacing the entire instrument cluster. So thanks for the input, I wanted to provide the findings for the benefit of anyone else having the issue. Will up date after I get it done.

 

That mind boggling. What is the combo meter?

 

No idea, that’s just what it says on the paper. It took like 2 hours and serveral techs at the dealership to determine.

 

Combo meter is what Toyota calls the gauge cluster/instrument panel.

Strange, wonder what the cluster has to do with trailer wiring?