Mine

Had to drop my fusebox out to see what was going on.
The two thick wires: Shortest end is plugged into the Crown, Longest end goes through the bulkhead and due to the gauge of it I'm assuming it goes to the battery or alternator to give the crown a more direct link to the battery. Will check in daylight to be sure.
My two small wires plugged into it: I've got one space used up in the white block (pictured) by two earths that also seem to be providing earth to something on the other side of the bulk head (although it doesn't matter if somethings not plugged into the crown if you've still got spaces on the crown, it's just an extension).
The key point seems to be that the wire in your hand should be connected to the crown and the other end should be going through the bulkhead, to what exactly I will check as soon as I can.