Continuity is checked with an ohm meter, with all power OFF on the circuit. It tells you is there's an open in the circuit, like a blown fuse, or broken wire. There may be a main fuse IN the converter, and like Norty said, it'll be a 30 amp. Also make sure the battery ground has a good connection to the frame. Google RV 12 volt system, and the generic schematics that pop up will give you a general idea how they're wired.
If you're going to "regret it in the morning", sleep until noon.
2012 Jay Flight 19RD
2016 Ford F150 XLT 2X4 SC 3.5L Eco Max Tow
2010 Tundra TRD DBL Cab (Traded)
2 new fluffy Corgis, Bayley and Stanley