Redoing the 12v panel

[KYAvion]

I’ve separated the 12v panel from the factory arrangement, and I can’t seem to figure out what the small black wire under the lower “Accessory” fuse does. A pic of the original box is attached showing the location—it’s the one with the fuse removed. Anyone know what this small wire goes to? The other “Accessory” is the horizontal fuse with the blue wire, which goes to the 12v amplifier for the TV.