2013 duramax

Thanks for the reply, ,,, at the current moment i have not got this warning without having the truck connected to the rv. on that note i have only driven the truck a couple times short trips.

2015 Chev Silverado 2500HD Diesel. I have been receiving the "check trailer connection" "service trailer brakes" for a good 4 years. Off and on. With or without trailer connected. Taken vehicle into shops and of course everything checks and tested good. Last year we swapped RV. Surprise, surprise... does the same with the new RV.
Started doing some internet research and have found where they are saying it's the trailer brake control that's mounted on the dash. Located behind the panel where you adjust the current going to the trailer brakes. Will be ordering replacement tomorrow. Seems to run around $30. Easy swap-out from video.

I have seen this message a few times with my 2015 Silverado. I have replaced a couple sensors but also found that other things can cause that message to appear. One word of caution, when it comes on, you lose your trailer brakes...

First, I was told by the dealer, never plug in the trailer with the truck running, turn the truck off before you plug in. Then, if you are still getting the message, try dialectric grease in the plug, the corrosion, or dirt, etc, can cause a bad connection, the dialectric grease helps. I have 2 trailers about the same age, with one I get this error more than the other, but usually stopping, turning the truck off, then plugging in getting a better seal, then it stops for the duration of the trip. If it continues, or you get that warning without a trailer, you have a bad sensor or something else. I have had to stop and unplug, re-plug more than once on a trip to get it to work correctly. The computer that causes that message is very sensitive. I have read other threads where people think they fixed the error permanently but my experience is that you can stop it for a while, but it comes back. Usually it is not a sensor but something with the connection between the truck and the trailer.

Many years ago I had a Service Trailer Brake System message on my 2009 Silverado.
A pressure transducer had failed. The local dealer fixed it under warranty.

On a previous trailer I had a brake wire rubbing inside the drum exposing the copper and causing an intermittent brake failure message. Sealed it up and never had the issue again.

You could have a brake wire shorted out to the frame of the trailer.

It's almost a given it's something to do with the RV.

I always start with the connector and at least for the last five to seven years it has been a connector issue. I vote for replacing it.

^Seems likely issue, doubt truck computer could read a brake adjustment, or lack of voltage to a brake.

Jerry