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Clicking brake light relay
#1
runninpony 
Hi everyone, I have some questions about my brake light relay (above the glove box) which clicks when I press the brake pedal and or turn on the hazard switch. My harness was refurbished by midlife and is working properly. I have a constant 12.4 Volts on the yellow wire going to the relay and the same voltage on the light green/red wire connected to the other side of the relay. (The clicking started after I connected my wiring, the brake lights and hazards were working then). Now no brake lights or hazards, just clicks! Could it be a bad ground or even a bad relay? Does the relay go bad? When I hit the brake pedal I have a huge drop in voltage (I have a voltmeter in the 3 gauge pod) but as soon as I release the brake pedal the clicking stops (it's more like one click every time I step on the pedal, if I keep my foot on the pedal it keeps clicking every 6-8 seconds ) and the voltage returns to normal! The clicks come from the brake light switch, no doubt and the relay gets a little warm to the touch if keep my foot on the brake and or the hazard switch is on. Thank you for your help!

71-73 Mustangs never die, they just go faster!
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#2
I think that's the circuit breaker going on-off.
Have you replaced some of the incandescent bulbs by leds? You have the right flashers? (you need 2) I think I recall they are directly connected to this breaker, check if you have power there, then I'd check at the break switch (its on top of the pedal arm on the booster arm) to see if you have power there. Also as the plate above the glovebox can become very rusty, make sure all the grounds are bare metal.

73 modified Grandé 351C. Almost done. 
71 429CJ. In progress
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#3
+1, that's the circuit breaker that protects the brake and hazard circuits. You definitely have a short. You didn't mention if your turn signals work, they use the same wiring to the rear of the car as the brakes and hazards and they are fused.

Both the stop light and hazard circuits run through the turn signal switch. If your turn signals work and don't blow a fuse the short will be at or before the turn signal switch. Because the hazard and stop light wires are separate until they connect to the turn signal switch, my best guess is that the turn signal switch is shorted. If your turn signals blow their fuse the short will be at or after the turn signal switch.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#4
runninpony 
I think I found the short after I removed the steering wheel and turn signal switch and re-installed everything. I have brake lights and hazards are working now as well (had to replace that relay) and NO more clicking! Thanks for your input guys!

71-73 Mustangs never die, they just go faster!
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