Maybe the ignition switch needs to on. Are you sure that what you're plugging into it is functional. A multimeter or a test light will tell you for sure if there is no power to the outlet. Sometimes the connections in the outlet fail. If you can get to the spade terminal (in back where the wires connect to the outlet) you can check power there. You may also have a "free" fuse if you need to run another wire to the fuse block.