brake lights no worky!!

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Ontheboulder

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hey all new here on this! this has probably been asked a million times but here I go. 1987 gmc sierra classic,v 2500. no brake lights! I had the left one working but not the right. the right turn signal was not working,so I tried switching the flasher,voila both turn signals are working, the 4 ways are working,the tail lights are working but I lost the left rear brake light that was working prior to changing the flasher.So neither side brake lights are working. Fuses are good.bulbs are good,. I have power into and out of the brake light switch, Orange wire constant hot and white wire lights up when the brake peddle is depressed.I have un- plugged the harness at the rear of the truck everything but brake light power!! Any ideas!!??? scratching my head here!!
 

Rusty Nail

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Got any pics of the taillights?
Show us what youre workin with!


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Ontheboulder

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sorry I don't just stock tail lights. This all started with just fixing the dashboard right turn signal indicator.after replacing all the gauge lights.got the dash light fixed but still no right rear turn of brake light, Both of the fronts work fine! Thinking it was just a bad light socket, nope.so after digging around on the internet,some said to just replace the flasher. well the flasher was working for the left side and the 4 ways but I changed it anyway.with the new flasher I got the right rear turn to work as well as the rest but lost my left brake light Hence no brake lights,even put the old flasher back in, still got both turns signals but no brake lights
 

Ontheboulder

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Like I said everything was working except the right rear turn and brake signal,now everything works except the brake lights.NO wiring has been done just bulbs and headlight switch replaced.
 

Ontheboulder

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I un plugged the rear lights from the harness running down the frame rail to the rear of the truck to check that as well. all good except for brake light power
 

fast 99

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Find the brake light switch under the dash. Should be power standing on one side, when the pedal is depressed, both should have power.
 

Ontheboulder

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Yup did that orange wire constant power,white wire lights up when the peddle is depressed
 

Ontheboulder

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another thing I tried was with the turn signal activated,pressing on the brake peddle. the turn signal-either side does not cancel for the brake light
 

Ontheboulder

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this stuff will drive a guy to drink!!! Heavily!!
 

JoeR Jr

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Remember that brake light power has to go through the turn signal switch in order to get to rear bulbs. They do this so the same bulbs can be used for both turn signals and brake lights. So your next move is to check brake light input into, and out of, the turn signal switch.

So that would be:
White wire is brake power into the switch.
Dark green and yellow would be power out.
 
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Ontheboulder

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Remember that brake light power has to go through the turn signal switch in order to get to rear bulbs. They do this so the same bulbs can be used for both turn signals and brake lights. So your next move is to check brake light input into, and out of, the turn signal switch.

So that would be:
White wire is brake power into the switch.
Dark green and yellow would be power out.
 

WP29P4A

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I would check the grounds for the tail lights, then the ground from bed to cab.
 

Ontheboulder

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thank you!! I have been reading that the brake light power seems to go into and through the turn signal switch.then on to the brake lights. this seems to be where i am at,
 

Ontheboulder

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I would check the grounds for the tail lights, then the ground from bed to cab.
I think all the grounds are good as every other light circuit is working, just no brake lights. starting to think it is in the turn signal switch, that may have to go to the shop to get done,not sure about doing it my self
 

Ontheboulder

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I replaced a turn signal switch in a 72 Chevy I had years ago,but it didn't have all the multi function switch stuff like this thing has. windshield wiper, High beam and the cruise control ,might be better to let my buddies shop take care of it ,if that's what it turns out to be
 

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