Get the wiring diagram from the dealer.The basic wiring is simple depending the size of the panel.It could be as simple as a bad splice or as was in my case a color blind installer.
However although I am usually way off base on electricaly issues, you do know that the newer Komfort trailers have a battery disconnect switch? (Ours is in the galley area). Pushing it in (off) shuts off all power from the batteries making everything appear dead.
We've had it happen accidentally a few times and members of our family get excited that our batteries have died. Of course simply pulling the switch out makes them happy again.
The very first time it occured we called our dealer, however, even he did not mention that we may have accidentally hit the switch. He actually suggested we needed new batteries.
We have not had this switch on previous trailers we've owned.
-- JP