I don't see a wiring diagram for your year, but the '04 is in Coach Assist. It looks like circuit breakers in the chassis electrical bay, street side frontmost. They should auto-reset any shorts. Though there could yet be fuses involved somewhere, I'd suspect the light switch. Been there, dun that. If someone tried "upgrading" to brighter halogens on a coach that perhaps didn't come with them, and as an attempted fix for the common weak headlight issue, halogens draw much more current, overheat wires and circuit breakers or fuses, and they won't work or won't work for very long. If they don't cutout, the dash switch itself's wiring posts can melt.
The proper fix for weak headlights has been posted about many times here, as you likely know, and members Roy Mueller and Bill Sprague did a useful video on the project some years ag:
https://www.youtube.com/watch?v=fmYyoILEhMYIf nothing else, reviewing the video can prep you for solving your issue.
All that aside, as an immediate move I'd check the condition of the switch. Others here may know of a fuse somewhere. And it's always possible a relay from the switch to kick high juice to the lights has failed. If the modification mentioned above has been done, it could be an added relay there that's out.
Joel