Eyeteeth,
They are mostly about batteries
Batteries are important. Did you check your battery? Has it been getting charged regularly (since you mentioned you haven't done anything on your RV in a long time)? What is the voltage at the battery? At the light sockets?
Is your DC circuit running off the battery right now, or off the converter? If the converter is plugged in then the 12v system is being handled by the converter.
Do the lights work when the converter is plugged in?
Do the lights work when the converter is not plugged in?
What is the incoming voltage at the 12v fuses?
That should be enough to get you started. If you don't have a multi-meter you need one.
