My truck is displaying a message to "Service Trailer Brake System" on 2012 Chevrolet Silverado 2500 HD

And the trailer brakes do not work. Can you tell me what will fix this problem?

2 answers 1 comment
should be under warranty at the dealer
Thanks
my 2007 done the same thing took a wire brush to the trailer hookup and sprayed pb blaster on it all works fine now