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Old 03-29-2020, 11:58 PM   #1
FatherandSon
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Brake & Temp warning lights turn on with headlights

I have a 69 C20. The temp and brake warning lights in my fuel gauge turn on and stay on when my headlights are on. When my headlights are off they remain off. Anyone know the cause/why this happens?
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Old 03-30-2020, 09:36 AM   #2
Mike C
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Re: Brake & Temp warning lights turn on with headlights

Most likely a grounding issue in the headlight circuit. Repair grounds up front at lights and add a ground strap possibly to instrument cluster.
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Old 03-30-2020, 09:46 AM   #3
LockDoc
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Re: Brake & Temp warning lights turn on with headlights

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Here is a thread on ground strap locations with some tips on making them yourself and installing them. Yeah, I know it's 4 pages long but it is a good read and it will cure a lot of electrical problems.....

http://67-72chevytrucks.com/vboard/s...d.php?t=422234

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http://67-72chevytrucks.com/vboard/s...d.php?t=829820

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Old 03-30-2020, 12:00 PM   #4
FatherandSon
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Re: Brake & Temp warning lights turn on with headlights

Thanks for the quick responses Mike and LockDoc! I'll check the grounds and let you know how it comes out.
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Old 04-16-2020, 06:18 PM   #5
FatherandSon
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Re: Brake & Temp warning lights turn on with headlights

Well my grounds were all good but a bit old and dirty so I went the extra mile and replaced all with new ground cables and ensured bare metal contacts but it didn’t solve the problem. Any other ideas?
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Old 04-16-2020, 06:21 PM   #6
60case
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Re: Brake & Temp warning lights turn on with headlights

check the dash ground
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Old 04-16-2020, 06:24 PM   #7
FatherandSon
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Re: Brake & Temp warning lights turn on with headlights

That was my first thought. It’s good.
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Old 04-16-2020, 06:38 PM   #8
60case
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Re: Brake & Temp warning lights turn on with headlights

printed circuit bad
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Old 04-17-2020, 12:46 AM   #9
FatherandSon
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Re: Brake & Temp warning lights turn on with headlights

Ok thanks
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