I was going to wire in a switch too, but haven't done it yet. You want to wire in the switch in series with the fuse, that way with the switch in the off position, no current can run through the fuse, which will act like the fuse is missing or blown.
You can either find the wire that goes to it from the back of the fuse box and cut it to add the new wires for the switch, or maybe relocate the fuse by putting wires in the fuse holes securely, and adding the switch in that way.
