i just got my 5th wheel out into service again. first time it has been out in alittle over a year. when i used the 12 volt lights all was good for about 30 minutes. then the lights started flashing on and off rapidly and continued to do this until i turned them off. i have had them on several times since with the same results. i never had to work on this system before and am not sure where to start. any suggestions would be appreciated.