1964 brake lights not working

[Helen Jean]

Brake lights stopped working on my '64. Have replaced switch at master cylinder, fuse is good. Taillights work for lights and turn signals.
Any ideas on what to investigate next?

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[sre]

Brake lights stopped working on my '64. Have replaced switch at master cylinder, fuse is good. Taillights work for lights and turn signals.
Any ideas on what to investigate next?

Power for brake lights go thru turn signal switch.

 

[biddle]

I updated your subject "1964 brake lights" to summarize your post. Good subjects get more responses.

 

[64ZCODE]

Try disconnecting the connector from the brake light switch on the master cylinder. Then, with the ignition on, use a probe to connect the two sockets in the connector. This should trigger the brake light relay and the brake lights should come on. If it doesn't trigger the relay, then likely a problem with the relay or wiring running from the plug to the relay or a faulty ground.

The power for the brake lights doesn't go through the turn signal switch.

 

[64ZCODE]

Helen, one other thought on this. You say the brake switch was replaced. Is the pedal firm after that or do the brakes need to be bled? Reason I ask is that it's pressure from the master cylinder that actuates the brake switch, and if you have air in the master cylinder then the switch may not be getting the pressure it needs to see. Doug

 

[Helen Jean]

Helen, one other thought on this. You say the brake switch was replaced. Is the pedal firm after that or do the brakes need to be bled? Reason I ask is that it's pressure from the master cylinder that actuates the brake switch, and if you have air in the master cylinder then the switch may not be getting the pressure it needs to see. Doug

Pedal is firm. I'm going to give your "test" a try to see if the lights work bypassing the switch on the master cylinder. Appreciate your insight !!

 

[74 Harley]

I don't remember the exact wiring for this, but the brake lights do go through the turn signal switch. If there's power at the pressure switch but the lights don't work then I would look at the turn signal switch.