Maryland

To clarify, it actually happened three times now, and battery is NOT actually low when checked, and throwing NO codes per dealer. It just won't crank/start. No sound no grinding nothing.... just won't start. Only power is horn and headlights. After unhooking both batteries for a period of time, and reattaching it has started. (Not sure of course if this action had anything to do with it starting, or if something just restarts after a certain amount of time. How do you get the truck out of park when this happens. Can't even do this when its down

Googling around and came upon this forum while trying to educate myself on possible solutions. Long story short: 2020 GMC 3500HD Sierra Denali 4WD Crew Cab – Standard Box Eng: L5P duramax 6.6L Turbo-Diesel Twice in 2 months. Won't crank, won't start. Can't even get out of park. Towed In dealership twice. They updated some modules due to service bulletins first time. Second time could find no issue and sent it home. Battery is not the issue (full charge) I suppose next step is directly contacting GMC? Has anyone had success doing this? Obviously, scheduled road trips and vacations on hold.