Brake lamp

[VintageTwin]

Description: My brake lamp on my 59 pan will not light

My brake lamp on my 59 pan will not light (stock-style wiring w/ [fork panel] terminal plate and behind coil terminal plate). The brake lamp will light, if I step on the pedal while the headlight is switched on. The taillamp will light too, with the headlight on. I replaced the brake switch (bottom of left frame)... (twice) [note: just because both brass pin-terminals can resist-turn, doesn't mean the switch is bad. There is a rubber bellows or sheet-diaphram inside the switch body that expands against contacts inside, when charged]and the pins, I now realize, are not cast in bakelite.] I also switched the two wires on the brake switch, and tried the brake pedal. No change. Brake lamp will not light. Changed 6 volt (big) bulb. I have no horn.

[59pan]

If my memory serves me the brake lamp switch just completes the ground circuit, there is no voltage there. I am assuming that this problem just started and is not the result of a rewire job. If so, check your ground. In my experience that is the source of most lighting problems. Use your meter to check continuity from the brake light circuit to the frame and then just trace backwards until you either find a loose ground wire or power connection.
Good luck.

[VintageTwin]

Not a rewire, it's apparently never had an operable brake lamp, since when I opened the tombstone lens (wrong lite for '59) the bulb was sitting askew, in the fixture, with only the bottom pin registered. The top pin was hanging out there, open to the air, corroded, from past hose-off cleanings (a cleaning method I've before since abandonded)... but then, changing and re-seating a new bulb didn't make it lite-up either. I will use your instructions and persevere until I source the problem. Thanks for a foothold on the problem.