Yes, did all of that.. so, since posting, I downloaded the trailer into the truck computer and now that it recognizes it, it only happened once and then no more-very strange.
Hi just got our 2021 GMC sierra Denali pick up. Absolutely love it got all the bells and whistles however I hooked on our small trailer and when I went to park the truck it said on the display shift to park before exiting vehicle. The lights stayed on on the dash and when I got out of the truck...