One pesky brake light not working

[bodayguy]

I can't figure it out. My passenger side brake light doesn't come on. The turn signal and the headlight beam function both work in this light, but no brake. The bulb seems fine, the wires seem fine. Driving me nuts.

 

I bought a retro-styled third brake light to install, thinking I could patch it in to the working brake light, but that didn't work either.

 

What's up with the wiring back there? Anybody know? I have the shop manual but it doesn't offer any advice.

[RivNut]

Because the same filament is used for both the brake and the turn signal, the problem is not in the wiring to the bulb or the bulb.  If I were you, I'd check the turn signal switch on the steering column.  The switch has to be aligned properly for all that to work.   You might also see if the brake light works with the tilt wheel in different positions. There's a cable in the steering column that will lead to these kinds of problems if the shielded cable is broken.  The wire inside the cable is good, but you can't get a good position on the turn signal switch because the cable isn't stationary. 

[bodayguy]

Thanks, that's interesting.

I don't have a tilt wheel but I do have other steering column issues. The horns don't work, for instance. And the turn signal switch doesn't turn itself off in one of the directions, etc.

[RivNut]

Jim Cannon, the '63 Tech advisor for the ROA, recommends that the spring that runs across the turn signal switch be removed, "it's over engineered."  See if realigning that switch won't work on the first problem you asked about. 

 

Probably time to pull the steering wheel and look at the self canceling device.  A piece could be broken or a spring has come unhooked.  Check the horns and associated wiring with a test light.  Start at the horns themselves with 12V and work your way back to the horn bar on the steering wheel.

[1965rivgs]

The brake light circuit travels thru the turn signal switch. Consequently when applying the brake and using the turn signals one light will function as a brake light and the other will flash as a signal light. The turn signal switch, whether tilt or standard column, must be in a neutral position for both brake lights to illuminate simultaneously. Try manipulating the turn signal lever while a helper looks for the non-functioning brake light to momentarily, depending on turn signal lever position, illuminate.

The over engineered spring comment refers to the tilt version of the turn signal switch, not the standard switch like yours. Good luck,

  Tom Mooney