I've had my truck for about 2 months and this was the 1st trip I took pulling my 21 ft Boat. The trailering app profile was easy to setup and the trailer lights safety checks are great, when working. I starting noticing yesterday when I hooked the boat up for the trip home that it was not sensed. I made sure the electrical connection was solid but still did not show the trailer connected. After turning truck off and resetting trailer plug several time, I started driving and it just started working. I drove 200 miles with it working and parked for a couple of hours. When I restarted, the trailer was not recognized again. I tried the same unplug and re-plug without success. I drove a couple of miles but still was not recognized. Also whenever selecting the trailering app, the display screen was black/dark. None of my trailer lights were working and I did not want to risk driving in rush hour traffic without trailer lights. I called the GM support (866-790-5600) and they asked me to shut off engine for 5 minutes to see it it would reset. That did not work. I tried again for 10 minutes and it suddenly started working. This is very disappointing. When it works, it's great but when it stops working I am stuck wherever I am. I will try to get into Chevy dealership next week.