Is your house battery is good condition and properly connected ? Some convertors put out rough DC power and use the house battery to "clean it up" so it is suitable to power your 12V stuff. You may be able to download a manual for your convertor here
; or try using dogpile search engine.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"