Hi there. Hoping someone out there can give me some pointers… I have just purchased a 2012 3500 CTD 4x4 SLT. My primary purpose for this truck is for hauling my camper and pulling a 4 horse trailer, which so far, I haven’t been able to hook up due to some sort of wiring problem.

The trailer has been fully re-wired and is fine when hooked up to my dad’s 2011 1500. Conversely, when I pulled my daughter’s (ancient) travel trailer with a 4 pin connection run through a 6 pin adapter, I had no problem – all lights worked (no brakes on the unit).

When I plug in to the horse trailer (6 pin connector), even with the truck off and the keys OUT of the ignition, the left front marker light, rear tail light and right license plate light come on. With the truck on, the EVIC shows a red trailer icon with a slash through it, and brake controller shows a flashing orange trailer icon with an exclamation mark, and the number “56”. None of the trailer lights work. (Other than the “on” lights mentioned above, the truck signals, etc. still function properly).

But the horse trailer is fine on the other truck, and the old travel trailer is fine on the 2012. I’m stymied. Any thoughts?

Thanks.

 

just a wild guess, is the wiring harness grounded as well as getting a ground thru the trailer hitch?

 

Does your Dad's 1/2 ton have a trailer brake controller? The reason I'm asking is that there may be an issue with your trailer's brakes. If he doesn't have a controller, the brakes won't operate, and may be a reason why the trailer is fine on your Dad's truck. Does your trailer have the trailer brake emergency disconnect kit installed? If the 1/2 ton has the brake controller, then there might be a problem with the controller on your 1 ton. There are threads about the factory brake controller causing problems. I disconnected mine a couple weeks ago and it seems like my problems went away. My controller would never stop my trailer either without using the slide lever. There is a member on here, Busboy, who had a major problem with his that the dealer fixed. I won't be using my controller again and will be upgrading to the Maxbrake.

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I am guessing your truck has a 6 pin AND a 7 pin connector installed, or are you using a 6 pin connector for both your trailers? Anyway, my guess is that your truck's 6 pin connector is wired improperly, or a wire has come loose inside and is touching another terminal.

 

Thanks for all your input and food for thought, between that and having read the entire brake controller thread, I should have some back-up when I try to get the problem covered by the basic warranty that has only 500 km left on it.

I did try both trucks on three different trailers and connector types today - all worked with the 1/2 ton and none with the 1 ton, so I'm good and sure it isn't a trailer wiring issue, anyway.

I'll come back and post the resolution once it's sorted out....

 

I had a similar problem on my truck. My dad's 06 worked fine with the trailer but my truck would have a red icon with a slash going through it and the yellow dealio on the brake controller with an exclamation point after it and no trailer function. Dad's truck worked fine. I thought for sure my new truck was junk until I inspected the trailer brakes and found that one wire on the right side was not connected. Seems my truck knew but dad's aftermarket trailer brake controller didn't care and didn't know. I fixed the wire and voila, trailer function came back and has been mint ever since. These new trucks are a little smarter than others I've come to find out. They also like a true ground going through the connector and not grounded through the hitch.

Good luck with your search. I would bet money it isn't your truck. I've been around lots of "re-wired" trailers and every one of them has been the problem.