Brake light keeps going out

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84GMCSierra

84GMCSierra

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Good Morning everyone. Got a question about my right brake light, on my 84 C2500. I've replaced the socket/pigtail twice now, and the brake light keeps going out, then will start working again. When it works, it goes for quite awhile then all of a sudden it quits working. Taillight on the right never goes out. Just the brake light. No issues with the left side. Ground issue? I'm thinking of replacing the harness as I know it's kind of a mess from being a farm truck at one time. Who do you all recommend for one that isn't crazy expensive? Or should I just take mine out and make sure it's in good shape?
Thanks and hope you all had a a good weekend.
 
AuroraGirl

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84GMCSierra said:
Good Morning everyone. Got a question about my right brake light, on my 84 C2500. I've replaced the socket/pigtail twice now, and the brake light keeps going out, then will start working again. When it works, it goes for quite awhile then all of a sudden it quits working. Taillight on the right never goes out. Just the brake light. No issues with the left side. Ground issue? I'm thinking of replacing the harness as I know it's kind of a mess from being a farm truck at one time. Who do you all recommend for one that isn't crazy expensive? Or should I just take mine out and make sure it's in good shape?
Thanks and hope you all had a a good weekend.
Click to expand...
when you say "out" do you mean it just wont work, it works with tail light at half brightness but it wont work at brake at full brightness, does the turn signal still work?

Or you mean the bulb burns out? If the bulb burns out on brake, but it still works for tail/turn, then you may just have crappy bulbs. The filaments are different, so you shouldnt have them both burn out for an issue only affecting one circuit.
 
Jgonick

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Do easy things first. Check the connections of DK-GRN-19 wire. Make sure it is connected well at turn signal switch connector (steering column) and the bulkhead and there should be one at the back of the truck on the run to the tail lights.

FYI- DK-GRN-19 turns into a YEL at last connection before right tail light

And yes, check the ground. see attachment.
 

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84GMCSierra

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Thanks everyone. Everything but the brake light on the right side functions normal. Might be cheap element but will check all the wiring
 
Jgonick

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84GMCSierra said:
Everything but the brake light on the right side functions normal
Click to expand...
Even the back right turn signal works with the brake light out?

They use the same filament of the bulb and wiring from the turn signal switch.
 
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AuroraGirl

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Jgonick said:
Even the back right turn signal works with the brake light out?

They use the same filament of the bulb and wiring from the turn signal switch.
Click to expand...
I thought th turn signal uses the smaller filament

Well, now that I think of it, that makes sense, because the turn signal would need to stand out from the tail lamp right? And when foot on the brake that needs to flash and be obvious
 
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AuroraGirl said:
when you say "out" do you mean it just wont work, it works with tail light at half brightness but it wont work at brake at full brightness, does the turn signal still work?

Or you mean the bulb burns out? If the bulb burns out on brake, but it still works for tail/turn, then you may just have crappy bulbs. The filaments are different, so you shouldnt have them both burn out for an issue only affecting one circuit.
Click to expand...
Nvm
 
Jgonick

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If- big “IF”. It truly doesn’t work when brakes are pressed. AND everything else works on back right (right turn signal and hazards). I would suspect a bad turn signal switch.

Turn signal switch provides different power sources to the DK-GRN wire depending on braking, right turn signal, or hazards.
 
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A bad ground can be confusing - what will sometimes happen (my friend Dave's 1987 Chevy did this one) will be if the ground is bad, current will partically flow back through the other filiment and make it seem like its working - you press the brake and it comes on, turn on the lights and it comes on - press the brake while the lights are on, and it goes off! On tail light and marker lights, I always suspect the ground to be at fault 1st. As old as these trucks are, corrosion and dirt have had plenty of time to get in and work their evil....
 
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Eliminate all the other possibilties first, but if you have random taillight issues that can’t be solved, more than likely you have a defective turn signal switch. There are a bunch on contacts that have to make and break connections for the brake and turn signals to function, it’s kinda amazing they don’t fail more often than they do.
 
84GMCSierra

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Blinker works fine
Matt69olds said:
Eliminate all the other possibilties first, but if you have random taillight issues that can’t be solved, more than likely you have a defective turn signal switch. There are a bunch on contacts that have to make and break connections for the brake and turn signals to function, it’s kinda amazing they don’t fail more often than the
Click to expand...

Matt69olds said:
Eliminate all the other possibilties first, but if you have random taillight issues that can’t be solved, more than likely you have a defective turn signal switch. There are a bunch on contacts that have to make and break connections for the brake and turn signals to function, it’s kinda amazing they don’t fail more often than they do.
Click to expand...
I'm already planning on replacing the switch after I get my engine next week. It's probably the original.
 
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