You are making this waaaaay too hard. I checked my '69 FSM, only two fuses in the circuit, tailight and instrument panel lights. Turn on the park lights, do you have tailights? If you do tailight fuse is good. With the park lights still on, check for voltage on both sided of the instrument panel fuse, do you have it? If you do the problem isn't the switch. I can't believe all this discussion about jumpering this and that without doing a couple simple tests to see if it is the switch.