Hi Robbie,
Very easy to fix this. The Power Converter changes 120V AC shore power into 12V DC to power lights and keep the batteries charged. In between the Power Converter and the batteries, there is a small 12V DC mini circuit breaker with a manual reset button. That breaker is one of several that are mounted together.
The buss bar with the breakers is located near your batteries and is usually covered by a red rubber boot. On one side of the row of breakers you'll find a copper buss bar that connects them. That's the side battery power feeds into. On the other side you have wires running to devices like the hydraulic pump, and to the Power Converter/fuse box.
On the output side, look for the 2 thick wires. One goes to the hydraulics and the other to the Power Converter. The one going to the power converter will have a teeny-tiny, very hard to see reset button. You may have better luck feeling for it. As soon as you press it, you should get power to your lights when unplugged from shore power. The pictures I've attached should help, but note that the breaker positions vary.
Btw, if you let this go for long enough, the batteries will discharge and no longer provide enough juice to keep the inverter running the refrigerator.