Welcome to the forum its a great place to get your questions answered. I would start by pulling the tail lights and checking the ground and power connections and go from there. there is hours and hours of reading in the library about electrical/lighting problems. I would recommend you do some driveway camping before your trip to ensure all things work.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho