My question is... in a hot Arizona afternoon camping in a diesel cargo van. can i run the diesel engine A/C, and take a nap. With a few carbon monoxide detectors placed here and there, would that be OK ???  

i have never done it in the heat; but have slept many many times in the van in the cold with the heater going. i have a conversion van. it seems to use lots of fuel though. a cheap hotel might be less expensive unless that is not an option.