Eurovan Camper-Winnebago, campre battery not charging

Camper electricals all work with charged camper battery, but the camper battery is not being charged by the vehicle charging system. The vehicle charging system is good. I suspect a blown fuse or open circuit breaker, but I don't know where or what exacly to look for. I cannot find a wiring diagram for the camper conversionj. I have the VW service manual two volume set for the vehicle, but it does not indicate where Winnebago connected the camper system to the vehicle charging system.