This switch is either for a TR4 or maybe a late TR3A or B. It has the spade
(lucar) terminal. The earlier TR3A switch had screw terminals. Either way
there are 2 terminals, not 1. Look at the wiring diagram. The stop lamp
switch has wires 22 and 17 connected. 22 is green / purple and 17 is solid
green. The switch is not power to ground but power (green) to the light bulbs
(green/purple). The stop lamp bulbs are grounded at their base.
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