"Check Trailer Wiring" Solution?

blackedout96 · December 24, 2017

I've had this issue now with two new trucks. The first a 2014 Silverado 1500 and now my 2016 Sierra Denali. Any trailer I ever connected them to I constantly get the "trailer connected" message followed by "check trailer wiring".

I'd love to blame the problem on trailer wiring, but the same trailers function perfectly when connected to Ford trucks and older GM's. This isn't an intermittent, works on some trailers not on others thing. Neither truck has ever cosistently operated the brakes on any trailer properly.

I've never seen a recall or GM acknowledgement of the issue, just wondering if anyone has ever found any solution.

bdbake01 · December 24, 2017

Curious myself. I have the same issue. When it happens, the brakes stop functioning until I turn the truck off and back on. Not cool.

jhplak325 · December 24, 2017

GM TSB for the issue - https://gm.oemdtc.com/6538/pit5311b-check-trailer-wiring-message-andor-service-trailer-brake-with-dtc-c1114-2014-2016-chevrolet-gmc

I have replaced the plugs on my trailers with the Pollak 12-706 plug and haven’t had an issue since and that was 2 years ago.

badge171 · December 24, 2017

Bad ground somewhere in the trailer. Some trailer's the ball will make the ground circuit. Not so, needs a dedicated ground on the trailer, The lighter the ground wiring diameter gauge. The weaker ground is produced.

MySilverado180 · December 25, 2017

I have had this issue on multiple occasions towing an RV. The 7 way connector is a very loose fitting, and when it loses connection, I get this error message on the DIC. Always have to re-seat connector and turn vehicle completely off to get it to reset.

Tried electrical tape to make it a tighter fitting. Worked better, but not great. Found that I had to tap the 7 way in further by a little less than 1/2 inch. It then grabbed properly and no more issues. Very tight fit when I did that, was almost afraid of breaking something.

Thanks for the TSB link above. I will also try getting the Pollak connector.

avgas · December 25, 2017

For some reason people who wire trailer plugs do not think they need to connect the ground wire. The ball just doesn't provide a good enough ground. Check the trailer ground, Its likely the issue.

blackedout96 · December 26, 2017

Ordered a Pollak plug for my trailer, we'll see if that helps.

The frustrating part for me is that I pull customers' trailers frequently and I can't go changing their plugs for the one time I tow them. I also have a 2014 F-150 for my shop truck and that operates all of them properly every time. I just have to use my personal truck when that's busy, which is most of the time.

The problem is so widespread and well known that GM must simply have no interest in fixing it. If Ford's 7-ways are forgiving enough to work on all trailers without special provisions, then GM should seriously consider trying a new style plug.

donaldbailey · May 11, 2019

my 2018 gmc is doing the ….. check trailer wiring …...trailer connected ...on dash display

trailer brakes don't work when check trailer wiring comes on

GMC put on new truck reciprocal didn't help

I changed trailer plug... twice

I ran separate ground from trailer to truck

still does it

trailer works fine on other peoples gmc truck

any ideas would be appericated

MySilverado180 · May 11, 2019

I also had similar issues and even had the dealer look at it. Everything was working correctly according to GM. Also noticed the loose fitting plug. Seemed too loose to maintain electrical connections. So I looked inside the receptacle and if you look closely you can see what looks like a quarter round piece of trim between the base and the wall. I figured my plug was going just above this, keeping it loose. Next time I towed, I had to push really hard to get the plug to seat inside that quarter round. It did! The plug was now tight, and never had the problem again. If you do this, just make sure the plug is aligned with the pins correctly and should be 95% of the way in, still loose fitting. That last 1/8 of inch is the push really hard part.

good luck.

donaldbailey · May 12, 2019

Thanks i will look at that

kenny_r · May 12, 2019

My truck does the same thing...2017 hd. There is just enough play on the trailer side connection that it triggers the message. Sometimes you can bend the tabs on the female/trailer side and it will work. That was the case with mine at least.