12 volt lights

I would suspect bulbs since inside and outside lights are not usually on the same circuit. RV wiring is, however, notoriously unpredictable. Two units of the same brand, manufactured on the same day may have completely different wiring setups. Depends on which plumber was stringing the wires.

A simple multimeter on 12volt probe light is your friend. Be sure you know which switch is "supposed" to control which light. Some interior lights have a secondary switch on the fixture.

Also, you cannot always find a blown automotive type fuse by looking. The best bet is to take a known good fuse and substitute it into each slot down the line. Like you look for a burned out Christmas tree light.

Good luck.

Of course the obvious question is have you checked the bulbs... Being a 2003 model and the fact that the automotive type incandescent bulb burn so hot it is about time for them to start burning out on you.

These 12V bulbs will draw around 1 AMP each so I imagine five dual bulb fixtures could be on one 15AMP fused 12VDC circuit.

These lights are parallel and probably the wiring is daisy chained from light fixture to light fixture. Some use the twist on connectors that may have come loose which could disrupt the light fixture further down the chain of lights...

I would drop the lens and do some quick look-see around the fixture. If you see any of those plastic twist type connectors you can inspect them for tightness or burn marks indicating poor connection over time etc...

No easy fix if the fuses check out and the bulbs are good other then inspecting for bad wiring and connections.

If you have multiple 12V wall switches involved this would be a good spot to look for poor connections or bad switches.

Simple thing first would be fuses and lamp bulbs... Pull the fuse out and look at it then plug it back in... The Automotive type incandescent bulbs will take on a very dark cloudy appearance when they burn out.

Might even be MICE infestation. They love house wiring...

Roy Ken