OK. First thing I would do it verify that the fuses in your converter are all good. Second thing would be to check for 12V at the switch. Is the light intermittent or is it completely dead at this point?
If you have power at both sides of the switch when the switch is on, but the light is not working, then either the light fixture itself has an issue or there is a break in the wire between the switch and the light. If there is no power at the switch, then either the power source has a blown fuse, or the fuse is not seated properly, or there’s a break in the wiring between the converter box and the switch. It is not unheard of for fuses to get corroded and cause intermittent problems.
2019 Bounder 36F
2003 Jeep TJ toad