Good progress. I think you now need to eliminate a fault in one side of the switch itself. You could do that in any of the following ways: A different switch. Could be just an on-off switch, one side at a time. Hot wiring, one side at a time, the input and output of the switch with the ignition on, by touching the leads together (as in the movies). If you're feeling nervous about doing that "live" then ignition off, join input to output, ignition on. Again one side at a time.Jonathan