There is an open plug under the console near the key. Just remove the two Philips screws at either side and viola. My visor plug is mounted into that console beside the choke lever and powered from that open plug.
FYI, there is another open plug near the guages for powering fuel guages, temp. guages, EGR's etc.
AC offer a splitter to make those open plugs available for 2 or 3 hook-ups.