In the end the actual problem was a terminal block under the "hood" that leaked power between + and -. I am unsure of the route that the semi short or ground feedback took but when the block was eliminated the instrument lights came on and the #41 fuse stopped blowing. I suspect that the feedback through the instrument lights damaged the first headlamp switch causing the lights to blink. The terminal block fed the audio system which was connected to the lighting system so that the audio lights would dim at night. I would never have figured it out if I had not, on the suggestion of a friend, tested the power supply to the audio. The + was 12v but the ground was 9v! It is amazing how ground problems can travel.