Service Trailer Brake

[hrspwr]

Hi everyone. I have a 2018 silverado 1500 with the integrated trailer brake controller. Recently I have been getting the service trailer brakes warning on the dash and trying to resolve it. Originally when i went to the gain screen on the dash, no numbers would show and it was completely dead. First test was to replace the module under the spare tire based on everything that I read which did not resolve the issue. I had the original battery in the truck and I knew it was starting to show signs of needing to be replaced which I did. Once that was done, it changed the behaviour of the message. Now when I turn the key to On without starting there are no messages. Once I start the truck I get a message for a split second but the gain screen is functional. I can adjust the numbers up or down without issue. Randomly as I drive though, i will get multiple warnings that i need to service the trailer brakes. As a test, i connected a known working trailer. The truck detects the trailer and the gain screen is alive (no longer grey and is yellow/orange). Hitting the brakes does not activate the trailer brakes at all. Using the slide, my truck brake lights will light up for a split second and then go out, then dash has the following warnings: check trailer wiring, service trailer brakes. I did have the dealer hook up to the truck and there is code U0422-71 from the electric brake control module with a description that it received invalid data from the BCM and P0562-00 from the chassis control module aux. 

Wondering if anyone can point me in the right direction? I also did the ground at the back where the module is under the spare and will be doing the other body grounds from the battery cable as well. As a test a known working dash module was also tested with the same results. Thanks in advance!

[mikeyk101]

I remember reading a while back that someone fixed this after finding exposed wire(s) along the frame rail. I think the insulation got scraped off and was shorting to the frame. Maybe start tracing the wiring from the rear forward. It will be a pain to do this but might help solve the problem. 

[hrspwr]

I did look at the hardness and didnt see anything obvious; can dive into the deeper. Also did continuity tests which didnt lead to anything. Looking for more info on that error and other areas to check.

[Hoginedgewood]

I believe the only thing that can be monitored is negative electrical current returning through the frame instead of the ground wire. It's just a guess, but that's how your home gfi breakers work and my theory is that is what's going on. I will be watching for what you figure out.