My father has a 2002 F-350, 7.3L with a 6-speed trans. It keeps draining the batteries overnight, the batteries and alternator are good so there must be something drawing a lot of power while the truck is off. Don't know if this is a common issue with these trucks but was hoping maybe someone has had the same issue with their truck and know a good place to start that's a common problem with the electrical system with the year F-350. Thanks in advance guys!