You should have a main 12 volt fuse panel somewhere. In my case it is in the bedroom in one of the overhead cabinets. Check for a fuse there.
The other possibility is that the first connection in a daisy chained run of light came loose.
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi