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Old 01-25-2017, 08:31 PM   #6
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tyeayo is a jewel in the roughtyeayo is a jewel in the roughtyeayo is a jewel in the rough
Join Date: Aug 2015
Posts: 23
Default Re: No brake lights working..all others work..need help!

Originally Posted by fdryer View Post
As you know, running lights are separate from brake lights and are on separate circuits. With ignition OFF, I think every vehicle is wired so anyone pressing the brake pedal will turn on rear brake lights - probably a safety issue when brake lights were designed to work with the brake pedal regardless of ignition switch position. The same can be said of manually turning on running lights, low and high beams without using the ignition switch. With this mind, your brake light circuit is the problem; brake pedal switches nowadays have at least two switches; one for the brake lights and the other for cruise control, the bcm where brake switch signaling goes to and output from the bcm to maybe a relay to power the brake lights. Presuming the bcm is fine leaves the brake switch by brake pedal and wiring at the rear brake lights.

Since brake lights are separate circuits from running lights, someone may have to press the brake pedal down while you probe each brake light socket for 12 volts. Be sure to test brake lights, not running lights. If you're lucky it may be a faulty brake switch and not wiring. The third brake lights are also wired as a separate circuit but run is parallel with brake light wiring so three sets of lights turn on for braking.
Thanks for that fdryer

I dug in deeper, and pressed the brake down with a bar, and tested for 12v to the brake lights, with the drl on i got 12v, with them off i got nothing....this is telling me there is a problem with power getting back to the lights when braking....

I swapped out the brake switch yesterday, and i even removed it from the bracket and had a buddy swivel it around and still no juice to the lights....I'm really stumped right now, only thing i can imagine is the NEW switch is also you know how i could go about testing that?


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