Since you are running the camper from two separate batteries and didn't run the wiring yourself you need to check that the wiring is fused at the underhood battery as close to the + terminal as possible to protect the wiring going to the camper. You should also fuse the second camper battery in the same way. . Normal 12 volt wiring colors are red + and black - and I don't really understand why the builders of these campers don't use type TC cable in red and black which can be purchased as easily as white and black. The way these campers are wired is really their weakest point.
Dsrtrat
If the truck is off and it stays very warm or hot then something seems worng to me. If it is hot only while the truck is running, then that is due to the coil being energized and it will get very warm. How warm is too warm though, probably best left for the manufacturer to advise on. But if I cannot hold a finger on the unit for a minute or so withoiut fear of getting burned I would be concerned.