My cargo lights don’t turn off; I swapped the bulbs for LED’s and never had a problem in 18months, even on the days were the doors have been open all day as we haven’t needed to move the van.
Apparently they’re on a timer but I’ve never taken any notice of how long they stay on for.
One of my jobs over xmas (which wont happen as I tend to think with all the best intentions but get nothing done!!) is to fit a switch on them.
The lights only have spade connectors going into them, so a switch and a bit of wire so I can put the switch in a practical place should do it