Bought a boat this week that was used for gigging at one time and the man had electrical outlet boxes in the front. I am trying to replace them and cant figure out what i'm doing wrong. I have a good size solid wire coming from a battery to the outlets. I am putting the positive on the brass screw and negative on the silver screw. Why am i not getting any light? When i touch the two wires together it sparks so i know i have power through the wires.