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hazard lights and 3rd brake light flashing at same time

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Old 02-19-2019, 07:27 PM
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Default hazard lights and 3rd brake light flashing at same time

I have a 1994 Chevrolet full-size blazer. When I turn my hazard lights they blink properly, but my 3rd brake light is also blinking... anyone have an idea what could cause that?
 
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Old 02-21-2019, 12:49 AM
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Bad ground? Reminds me of how trailer lights can act all wonky because the current is flowing through a different path than you expect.
 
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Old 02-21-2019, 03:50 AM
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Could be. I am pretty sure it has been wired for a trailer brake controller and some point previously. Currently it does not have one installed though. I do have a pigtail for a small trailer I use now and then. I know the turn signals and brake lights work fine. I have not visually checked hazards while the reailer is hooked up. I have no idea where to inspect ground connections for this particular circuit. I'm pretty bad at electrical diahnosis 😭
 
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Old 02-23-2019, 02:04 AM
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so I have not looked for issues with grounds yet. I did just replace my left tail light circuit board again cause that thing melts and stops working every 6 months or so. I plan to put LED bulbs in the rears just to hopefully stop it from melting (hoping less wattage will help....) I also installed an electronic flasher for the turn signals and an electro-mechanical flasher for the hazards to replace the thermals in both. the turn signals flash a little faster than I am used to, but not hyperflash by any means, so its cool. Its quieter and overall im happy with it. But none of this changed the 3rd brake light flashing at the same time as the hazards. Anyone know where the ground for my hazards would start and end? Im really bad at vehicle wiring, I don't know where the grounds for these would be attached to the truck at. also to complicate matters even more, my truck has an alarm installed and I believe it had a trailer brake and trailer wiring ran. So ive got quite a nest of wiring stuck up under my dash that is a huge mess. Any pointers on where to look would be much appreciated. I don't mind taking things apart and looking, just need some direction of where to begin.

thanks
 
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Old 02-23-2019, 03:46 AM
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As the hazards tie the brake lights together to flash I would think the third light flashing too would be normal and even if not I really don't see where it flashing too is a problem.
 
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Old 02-24-2019, 03:00 AM
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well if its supposed to be that way then I don't care at all. My concern would be if its not supposed to do it, I really don't want to have melted wires to deal with, or my truck having an electrical fire or something.. so that would be what im worried about. Anyone else on here with a 92-99 suburban/Yukon/blazer/Tahoe/jimmy that can confirm the 3rd brake flashes with the hazards when turned on?
 
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Old 02-24-2019, 05:10 PM
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Does the third brake light flash with either of the turn signals, or just with the hazard lights?
 
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Old 02-24-2019, 11:12 PM
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only with hazards.
 
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Old 03-06-2019, 07:26 PM
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Mines a 99 blazer 4 door lt, 3rd light doesnt flash. I just picked up a 00 jimmy 4 door slt, havent tried the hazards yet tho...
 
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