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Discussion Starter · #1 ·
I'm new to chevy but have been a mechanic for about 6 yeas now and I never run into this problem before. The problem seems to be in the rear wiring but I'm not positive. Headlights, brake lights and directionals work fine until either the headlights are turned on or input my foot on the brake. Then the directionals blink faster and in the rear the light opposite of what the switch is switched to lights up. And thoughts please help need truck for work in couple of days thank you.
 

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Just a guess here but blinkers normally blink faster when there is a larger load being placed on the flasher. Combine that with the unexplained lights coming on when you step on the brakes or have the headlights on, I would guess there is some kind of a shorting issue going on. Where it would be? I have no idea. But that is just a guess. I hate electrical problems!!!
 

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What area of the country are you in?

There is probably a ground that is bad/corroded on your running/brake lights. When the ground wires get corroded there is added resistance so when you add a load to those lights affected the resistance forces the power to other circuits nearby. Its kind of like damming up a creek, the electricity has to flow somewhere so it backs it up like traffic jam trying to get to ground. I would clean the sockets really well especially the ones under the bed of the truck (if equiped) and put dialectric grease on all the connections. Also clean off the ground at the battery and where it mounts to the engine/frame. If you follow the wires from the back it should come up into the engine bay and try to see if there is a way to clean those connections as well.
 

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Discussion Starter · #6 ·
Central maine area... The ground in the rear is clean already check it but I just discovered when I unplug each taillight assembly one at a time the blinkers work normal again. Any suggestions to that? Lol
 

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I guess leaving one of the tail lights unplugged isn't going to be a solution???
 

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Chevydude2013 said:
Central maine area... The ground in the rear is clean already check it but I just discovered when I unplug each taillight assembly one at a time the blinkers work normal again. Any suggestions to that? Lol
Your a Mainer, you dont use salt so its not as corroded as my truck but not like living in colorado. One way gramps (he owned an electronics business) used to rule out a bad ground was to tap into the ground for the taillights/runnign lights/reverse and wire a second ground just laying next to the truck directly to the battery. It is quick and easy and if it changes your blinkers then you know that you have a ground problem, he allways said "you can never have too much ground".

All your symptoms though make me suspect a bad ground. I could be wrong but that is where i would be looking first, after checking for burned out bulbs of course. i would be trying to find any place the ground attached and cleaning it with a wire brush or sandpaper.
 

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Chevydude2013 said:
Obviously not then I'm out one tail light. That would still leave me with a problem
Sent from AutoGuide.com Free App

Yeah I'm sorry. I was kinda making a joke there but I'm sure you don't think it's too funny
 

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Discussion Starter · #11 ·
It's all good esox I was just in a bad mood this truck has been pissing me off since I bought it a few weeks ago. But I have always owned foreign trucks and I'm sick of there high priced parts and other bull. So I bought a chevy cuz that's what everyone told me to do. But trust me if I could get away with one tail light till I figured it out I would lol.
 

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Discussion Starter · #12 ·
Thanks everyone I thnk you all help. Little bit and hopefully the two tail light circuit boards I bought will fix it. Everything everyone has said has led me to thinks it prolly that. And all my diag does too.
 

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Let us know how it all works out.
Oh, and good luck with the fix.
 

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Discussion Starter · #16 ·
Tested the circuit starting at brake light. Nothin on brake hot wire (brown) and ol on bothe directional wires. Hence my turn signal switch is shorting out. If someone can verify this for me I am horrible with electrical.
 

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I have seen a similar problem with a two filament bulb when one of the filaments broke and was intermittently contacting the other filament. Lamps worked when the truck was parked and 'looked right' until the truck was being driven.
 

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Discussion Starter · #20 ·
So back to the diagrams. Was for sure it was the turn signal switch. But I guess not. Pulled out the brake light switch if anyone knows any tests I can do with it out to see if it's good or not would be greatly appreciated.
 
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