What does the “unknown” fuse go to?

[Mcm]

Ok, bare with me, I’m not proficient in this as of yet. We have a 2007 x23b. The power quit, the ac quit, fridge, everything. Went to find this fuse that people told me to check that is near the battery box. There is no battery. The previous owners must have removed it. The fuse is there but not hooked up. The wires there were corroded and taped off, etc. Cleaned them, etc and everything started running. Well not sure about the a/c yet, as we took that apart thinking it was a separate issue. My question is, what is this unhooked up fuse for? Should it be hooked up? We don’t have an electric jack or electric awning, if that makes a difference.
Thanks all!

[RogerR]

The fuse up front near the battery box is made to protect the battery from a dead short. If you have no battery than all the 12 volt power for lights, etc. comes from your converter. The air conditioner, microwave and the converter that provides 12 volts runs on line power and is not effected by a battery or any part of the 12 volt system. Typical 12 volt items are lights, ceiling fans, furnace fan, sometimes needed to run refrigerator even when on propane but not always.

Several good youtubes with explanations of your power systems and how to trouble shoot them.