I have a 1994 Peterbilt 375 that we haul grain with. I found out last fall that it would randomly shut off when the lights were on, even while driving. The truck will start right back up no issues once I turn them off. However, it does not happen all the time and is random. I am assuming I have a short somewhere but don't really know too much about this system or truck to dive in and start taking things apart. I also do not have a wiring diagram. Any thoughts?