Starting a new thread on my issue.
Going down the road I constantly get the message trailer disconnected/connected.
I use the round 7 pin connection with trailer brakes. Never lose lights or brakes. Have installed new trailer plug, double checked all wiring on truck and trailer. Reading other posts discussed rusty trailer ***** so replaced that and cleaned coupler with rotary wire brush. What else to check? Gotta be wiring somewhere since it does it going down the road. What truck circuit determines if there’s a trailer connected?

 

I was getting that often and found that some of the pins were just bent in too far and losing contact. I GENTLY pushed them out a bit and it fixed the issue.

 

The trailer brake circuit triggers that message.
I was getting the same message, but I have electric/hydraulic brakes on my boat trailer and there can sometimes be compatibility issues with those systems and the factory brake controller.
When I had issues with the lights, I found that the harness connector where it plugs into the back of the trailer connector socket on the truck had turned into green chia pet.
Replacing the socket assembly and the y connector for my tailgate light strip fixed the issue.

 

Sherman, thanks! Opening the terminals on the truck’s connector seems to have fixed it! Towed RZR 60 miles yesterday and didn’t get the disconnect message once.