The converter is actually the power device that turns 120v shore power (plug in power) to 12 volt DC. It's responsible for charging the batteries as well as supplying 12 volt power to any onboard electronics while plugged in. It may be difficult to know there is a problem however as it the batteries will power the system as long as they have a charge. You might only find an issue wen the battery finally lose its charge and all 12 volt systems stop working. 12 volt to 120 volt uses an Inverter.
No, your converter switch is for when you have no shore power and you want to watch television or plug into one of the round recepticals next to the normal wall plug to feed some device AC power. Check your 12 volt switch to see if its on if you are on shore power but nothing is on.
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