If the blown fuse indicator isn't working, you don't have 12V to the fuse box. Does anything 12V work? If the battery has voltage, you have an open to the fuse box. Disconnect the battery and check if the cables have 12V from the converter.
If either of the above have 12V then you have an open wire or circuit breaker.
I have a 30A automatic resetting circuit breaker that feed the box. Most are a small aluminum box (about 1 inch square) with 2 studs for the wires to go on. They normally have a tab allowing them to be screwed to something.
I have heard of these going bad. If you have one and it were this that was open you could temporarily jumper it until you got a replacement.
On my 5th W, I have a 30 Amp inline fuse in the battery compartment that removes the battery from the circuit.
You could temporarily put ice in the fridge to help maintain cool. At this time of night that's a problem. I know, not much help.