Sean, are you talking the wire that goes to the ignition switch???? If so, I would say the extra jumper could be for an accessory that you would want to have powered with the ignition switch in the off position.... If you do use the jumper, make sure you install an inline fuse in the wire for the accessory you wire into it... Personally, I don't like anything except the lights that isn't "powered up" by the ignition switch.