Loaded up my 2015 yukon XL Denali for an out of town dog show. Got ready to leave the next day and battery is dead. Got a jump and took it to the dealer. They said everything is good, I must have left a door open overnight. Got back from our trip and did some troubleshooting. Turns out that I had loaded the load space so full before the trip that I then opened the rear window, put in a few more things right next to the tailgate and then closed the rear window. Next day......dead battery! turns out that if you open and close the rear window, the interior light do NOT turn off. If you open and then close any door after doing this, the lights turn off. If you lock the truck, the lights turn off. If you lock the truck, then open the rear window the interior lights turn on. If you then close the rear window, the lights turn off. So the vehicle knows to turn off the interior lights after the rear window has been closed, buy only if the vehicle is locked. If you close the rear window and do not lock the truck or open and then close a door, the interior lights stay on and kill the battery. This is just a heads up for the reast of you as this little design problem cost me three hours at the start of my trip.