The original switch, as you know has three terminals, but only two were used. When you turn on the switch, it powers both the ignition terminal and the other terminal (maybe for accessories) and when you turn off the switch, it disconnects the power to both. You can use a multimeter to see how each terminal is powered.

I’ve included a picture of the electrical diagram for a ‘51. Keep in mind that if you converted to 12 volts the wiring will be a bit different.
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Last edited by Phak1; 09/19/2020 1:35 AM.
Phil
Moderator, The Engine Shop, Interiors and Project Journals

1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube
Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes
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