brake switch smoke!



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Sporty59
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Location: Lancaster, PA
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brake switch smoke!

Post by Sporty59 » Tue Nov 05, 2019 7:02 pm

Picked up Sporty today after she got the new leaf springs! Wow, what a difference. After arriving home I was trying to find the issue I'm having with the turn signals. Blinking fast as if there is a something grounding out. Both sides. With tail lights on, signal barely visible. Almost like a short. But, I'm trying all possibilities to see if and when various lights are working. As I'm using turn signal, lights on and braking the pedal got stiff, also noticeable smoke and smell from the engine compartment. I see smoke under brake switch, looks like fluid leaking on the wires. I shut off the car, it seems to dissipate, but as I pressed the brake pedal with engine off the smoke began again and I realized it was electrical. Duh.I disconnected the two leads to the switch and one was melted. Initially I thought a bad brake light switch, but could this be a wiring short elsewhere? I really dislike tracing wiring issues, any suggestions would be helpful. Right now underivable again until I can use the brakes!

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Faulkner
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Re: brake switch smoke!

Post by Faulkner » Wed Nov 06, 2019 9:47 pm

Uh-oh!

The thing to remember about brake lights: There is a left and right indicator that you are stepping on the brake. When you are turning at the same time you are stepping on the brake, the brake light on the side where you are turning is intermittently turned off and on, to indicate the turn. (The car behind you still has an indication you are braking, because the light on the other side stays on.) This is independent of parking lights, which is a separate filament.

For this to occur, the power wire from the ignition switch, to the brake light switch, to the brake bulb - must go through the steering column and the turn signal switch. If the wire melted on the brake light switch, you could have a short to ground somewhere in the steering column, or somewhere in between.

I feel your pain! If you don't own a VOM, make the investment - they're cheap these days. Disconnect power, disconnect connectors, and buzz out the wires to ground. It's laborious and painstaking, but the only way I know to identify shorts (and undoubtedly, a wire carrying power shorted to ground to cause the melt).
"If it's new, Image Plymouth's got it!"

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