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Discussion Starter #1
Hello All,

I am having an issue with the brake light switch on my 65 coupe. Even at the brake pedal resting position, there is continuity between the terminals on both the old switch and the new one I just installed (conversely, neither switch has continuity between the terminals when I removed them from the brake pedal).

If I understand the schematics correctly, there should only be continuity when the brake pedal is pushed, sending 12V to the turn signal switch. I think this may have burnt up my turn signal switch as well, but I will deal with that separately.

I know the previous owner had a new power brake system installed. I am wondering if the new master cylinder plunger assembly might be the wrong shape/size and doesn’t have enough play to allow the switch to open at rest...

Anywhoo... thoughts?

Thanks!
 

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Let me guess, your car has a clutch pedal.

Worn out pedal bushings allows the brake pedal to drop and it makes the switch stay on. If you put your foot under the brake pedal and pull it towards you the lights will go out for a moment.
 

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Discussion Starter #4 (Edited)
It has both bushings/washers... I’ll have to try pulling-pushing up on it, but I wiggled the pedal around with my ohm meter on it and could not get it to break continuity.

Has anyone retrofitted a different type of switch for the brake lights other than the original/standard type switch?

Also, no clutch - it’s an auto.
 

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They have the brake light sensor that works off the brake pressure. It gets connected into the brake line. When the sensor detects pressure, the wires get connected.
Those type of switches don't last that long. There is a post on here where a guy used a 72 nova brake light switch, a muffler clamp and welded a home made bracket to the clamp. There is a picture of it somewhere.

I did the same thing, but just made a bracket and bolted it to the support in front of the brake arm.
 

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I got tired of trying to get the mechanical switch to work on my '66 and installed a pressure switch as has been mentioned. Works fine. I suspect most modern cars use a pressure switch, not mechanical.
 

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64 1/2 D Code Coupe,
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Could the plunger rod from the brake pedal to the MC be too long applying constant pressure to the mechanical switch?
 

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Discussion Starter #10
That’s what I was wondering...I just don’t know much about the brake system added. I think the rod is threaded, so maybe there is some extra length that can be removed. I just wish the shop that installed it would have adjusted it correctly when they did it (it that is the case).
 
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