How do you fix a burned wire that is plugged in at the fuse box under the Bat sign?

To fix a burned wire that is plugged in at the fuse box under the Battery sign, the wire will have to be removed and a new one soldered in place. Before doing this, find the cause or overload that caused this wire to burn in the first place. It could be that a fuse of too high an Amp was placed in the fuse box by mistake.