bharten

I have this EXACT same issue on my 2021 3500HD Duramax flatbed. Bought the truck in June and hooked it up to a brand new tilt deck equipment trailer. Everything was fine for a month or two, then the DIC starts chiming “Check Trailer Wiring/Trailer Brakes Connected”, randomly, but constantly. Had the truck looked at, and the shop found two of the factory blades on the plug pushed in a bit, so they replaced the plug receptacle on the truck. That did not fix the issue. Dropped the trailer to a shop to look over the brand new trailer wiring, test the brake magnets, look at all the connections, and everything looked good. Had them replace the plug on the trailer, in case there was something internal with it, and that didn’t fix it. My 2021 truck will tow my older 2005 Featherlite enclosed trailer, with electric brakes, with zero issues, so that leaves the trailer suspect, right? Not really. When I tow the equipment trailer with my 2011 3500HD Duramax, it has zero issues with the trailer. So which one is the issue? Why do that specific truck and that specific trailer not play well together??? If I bring the trailer back to the dealership, they are going to tell me it is a truck problem, since everything checked out OK by the other shop. I am ready to pull my hair out on this one.