NHTSA Complaint #11574990 — 2022 GMC SIERRA 2500

Trailer brake controller that is built into the truck intermittently works when towing a trailer. I will be towing down the road and all of a sudden I will get a warning on my gauge display that says “check trailer wiring” and the light that indicates that the trailer brakes are working goes out. Meanwhile, all of the lights on the trailer still work. After about one second, another message appears and says “trailer brakes connected” and the light on the brake controller comes back on. When this happens, the larger screen sometimes has a message that says “trailer brake gain recalled” but sometimes it says “brake gain not recalled”. When the message “check trailer wiring” comes on, the trailer brakes don’t work. The trailer brakes start working again when the message “trailer brakes connected” comes back on. You can feel this in the truck, especially when it goes off, on, off, on, etc while you are trying to slow down. You literally feel the truck surging as the brakes are intermittently being applied. I have taken the truck to a GMC dealership and they were not able to duplicate the issues since the issue only happens when the truck is hooked up to a trailer that has trailer brakes. I had a certified RV mechanic inspect the trailer brakes and they are working like they should. I hooked the same trailer up to a Ford F-250 and had zero issues. I hooked the same trailer back up to my GMC and immediately had the same issues. I am taking the truck and trailer to a different GMC dealership on March 11th to see if they can duplicate this and diagnose the problem. I called GM corporate customer service and they were basically no help. This is a big safety issue because the truck is not telling the trailer’s brakes to function like they are designed, which makes it much more difficult to slow down, especially going down hill. I have done a bunch of research on this problem and found numerous online forums on this topic, so I know I am not the only one experiencing this