[MattHelm21]

I have had insignia TV's in the past and they have never operated on 12 Volts DC. You don't mention the size of the TV but what you describe sounds like a flat panel which is small enough that to conserve space, they moved the internal 110 volt voltage converter which you never see on most TV's to the outside in order to save weight and space in the panel itself. You likely need the RV on shore power or a generator for this TV to work. The brick may convert the voltage to DC but most TV's and computers for that matter use multiple DC voltages some of which are higher than 12 volts which is why they can't just be wired into the RV's 12 volt system directly.