If you have reached the limits of your comfort zone and need to call in tech support I would rather use a licensed electrician over the the local RV service center. Although I am not a code qualified commercial or residential electrician I did do a lot of work under supervision and haven't encountered major differences between RVIA and NEC. The labor hour costs might actually be less or close to what a service center will charge plus you won't have to wait in line for maybe weeks to get the coach fixed. As an added bonus they'll come to you rather than having to drive the coach somewhere. The hard part might be finding a tech who will work on a coach. An RV might be a bit exotic in their view.