This involved the CARGO LID at the rear of the vehicle. I could have been KILLED or TOTALLY PARALYZED by the incident. I have not brought the vehicle to a dealer, nor has any other authority inspected it. Also, there was no warning. During cold weather days, the lid would open normally and when it was fully opened it would start descending in small steps. I then would physically lift it to the full open position and it would stay there until I was finished (loading or unloading) then it would close normally after I pushed the ‘close’ button. This particular cold day incident, I physically lifted it to the top then went to get a box to load. As I approached the vehicle the lid came slamming down with a bang. Had I gotten there a few seconds earlier my head and neck would have been inside the cargo area and the lid would have slammed down on my head or neck, possibly killing me or paralyzing me with a broken neck. On non cold days the lid operates normally. However, I now use a two by four to prop the lid in the open position regardless of the daily temperature.