You said: THe only thing that works is the 12 volt lights when plugged into shore power.
Well.. Though there are exceptions.. One I know for sure is the Magnetek 6300, On most RVs this would indicate the converter *IS* working.
On the 6300 however there is a relay and perhaps a fuse that is NOT working.
On most all RV's there is a fuse or circuit breaker in the battery lead, either near the battery, the Battery control center, or the converter,, This too may have either Operated (Fuses, operated = blown) or malfunctioned (Breakers).
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times