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Discussion Starter #1
So ever since I have had my truck, 2 years now, I have had a problem with the left blinker. When the lights are "off" all the blinkers and hazards and brakes are normal speed and everything is biscuits and gravy. But whenever the sun goes down and I have to turn my lights on, all the lights work and the hazards are normal and the right blinker is normal but the left blinks fast as if a bulb were out. Now I have replaced all the bulbs before (I might do it again next paycheck) and the problem persists. So I am stumped. I've also looked around for people with similar posts and haven't had luck there nor google searches. I've looked for a wiring diagram because I have a feeling its a bad ground. This problem happens if my lights are "off" as well if I hit the brakes which tells me it has to do with the tail lights wiring since the front would do it all the time if the front was the issue, but only when I brake (when the lights are "off") or when the lights are turned on does this happen.

Also, I want to add that my headlights stay on all the time. Since I got it they have been like that, if I turn the lights on all it really does is turn the running lights and tail lights on. Not sure if that could be part of the wiring problem or not.

Any ideas and help would be appreciated!

This is a 1998 Chev K2500 4x4 ext cab with ~207500 350 vortec 4l80e

P.s. if you know where the grounds are that'd be good news to me, as I said I've been looking online but haven't had much luck.
 

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Discussion Starter #2
Bump, BTW its not the signal switch. I tried that last year.

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I guess all I would like help with is finding the grounds for the blinkers in the rear.
 

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My guess would be grounds or someone has been into the wiring at some point. I do not have a schematic, sorry.
 

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fluid probably low
 

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Discussion Starter #5
My guess would be grounds or someone has been into the wiring at some point. I do not have a schematic, sorry.
Yeah that's what my guess is too cuz they are aftermarket tails. I replaced the trailer hookup which was very shoddily done, no heat wrap, the whole thing had corrosion buildup and was rusted out. Most of the wires were barely holding on. Thanks for a reply, hopefully someone has dealt with the grounds around here and can point me in the right direction.
fluid probably low
Oh yeah I should fill that up... lol

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If they are aftermarket tails then they are honestly probably the faulty piece of the equation.
 

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Discussion Starter #7
I'm not sure about that because all the wiring is the same because all they are is a different housing. They aren't LED or anything fancy, just a clearer housing. Here's a picture


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I'm guessing the grounds are just old and probably have some corrosion or something is shorting them. Maybe its not but it has to do with the dual filament because it happens when I press the brake and also when the lights are on (that's when it does it the fastest and all the time)
 

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Discussion Starter #8
I would just follow the wires if I had the time but I'm busy with school and finals are coming up really soon, so I can't do much until the end of this month.

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Ah I thought they were LED. Maybe the bulbs used? Look to see if any wiring has been tapped into.
 

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Do those lights still use the factory curcuit board style light holder? Or are they the one's with individual sockets? The ones that will reuse the circuit boards have random issues when they burn up the copper trace inside and sounds like it's back feeding the ground when you need the higher wattage side of the bulb.
 

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Discussion Starter #11
Ah I thought they were LED. Maybe the bulbs used? Look to see if any wiring has been tapped into.
LED would be cool but they're just regs. I'm gonna go check how the wiring looks again to be sure but last time I checked it was fine near the sockets.
Do those lights still use the factory curcuit board style light holder? Or are they the one's with individual sockets? The ones that will reuse the circuit boards have random issues when they burn up the copper trace inside and sounds like it's back feeding the ground when you need the higher wattage side of the bulb.
They are individual sockets

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Discussion Starter #13
Do they look like regular bulbs? Try new bulbs maybe :shrug:
I replaced them last year when I tried figuring it out but nothing happened. I'm thinking of grabbing new bulbs again though

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Discussion Starter #16
Don't know if the videos gonna work, the others failed to upload so I made this short one.

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Discussion Starter #17
Now that I have taken apart the taillights I got the motivation to finish figure out where the wiring goes. From a quick glance it didn't look like it went anywhere but the trailer hook up. When I get back home I'm going to really get under there and check it out. I'll post my findings with some pictures if they help

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