Fuse Box is a feature located across all maps in Classic AI Gamemode that controls the lights and affect certain ghost abilities.
Functions
Once a hunt starts, the lights in the current room the ghost spawned in will start to flicker (as long as the lights were on). Television and computer screens, part of ghost interactions, also emit light. The ghost can turn on these screens at any time. You are sometimes able to see these lights through walls, and thus can be slightly disorienting.
Effect on ghosts
Lights can also effect ghosts, specifically the Mare and the Wisp. When the lights are off, Mares receive a significant speed boost. The opposite applies to Wisps, with them gaining a significant speed boost in the light. It's also (somewhat) important to note that at the start of a round, if the ghost turns on the lights in rooms there's a good chance that the culprit is a Wisp.