I am a 2005 2500 and I just bought a used trailer to tow my tractor. I have the tow package and the trailer used the 7 pin rv connector. I was checking my lights on the trailer and noticed that my passenger side turn signals don't work. I also noticed that when my truck is turned off, no brakes applied no lights on, the rear trailer light is on all the time, like the brake is applied (it is bright). The only way to shut it off is to unplug the 7 pin connector.

I am not sure where to start to find my problem. Does this sound like a truck side problem or do you think it is a trailer problem? Any suggestions on where to begin?

Thanks for any help you can provide.

Jason

 

Quickest way is to find a budy with a trailer and plug into his. Same problems, it's the truck. No problems, it's the trailer. It's been my experience to start with the trailer, but don't completely ignore the truck. You can take any old test light or voltmeter and check the truck plug in about 2min.

 

I did test the plug on the truck and I thought it checked out ok but when the brake light on the trailer stayed on, it made me wonder. If the truck brakes are not on, what is supplying power to the brake pin on the plug?

If it is the trailer, is it a grounding issue somewhere?

 

someone has the wiring on the trailer all screwed up. There is a constant 12v line in the 7pin connector. It is used for light's and accessorys. It sounds like this is wired too the brake circuit. Maybe this will help. The Black or Orange should be hot all the time, I don't remember which one it is off hand.

 

Double check all the grounds on the trailer. If they're is a bad one the voltage will search for a ground and back feed through another curcuit.

 

something is shorting out