81 electrical help

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Sep 16, 2023 | 03:56 PM

ole softai

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From: Ponchatoula la

81 electrical help

Having an issue with with my volt gauge. Old gauge went out and put a new in. Now when I adjust the lights on my dash with the light switch the volt gauge drops to zero. Installed a new light switch and same thing happens. If I turn dashboard lights off volt gauge reads normal. Still showing 13.5 at battery all the time. Also now my tack reads no lower than 1500. I have the shop manual and checked alternator and as many grounds I could find. It’s an 81. Car is mint and no issues before. Thx E J

Sep 16, 2023 | 04:13 PM

calwldlife

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From: Southern Cal Ca

St. Jude Donor '22

I am trying to follow the events that happened.
Sounds like a dash bulb is making connection with volt gauge.
so,,, remove gauge cluster and inspect.

Sep 16, 2023 | 11:18 PM

ole softai

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From: Ponchatoula la

Yes

Plan on looking into the plug behind the cluster tomorrow.

Sep 17, 2023 | 08:36 PM

ole softai

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From: Ponchatoula la

Update

Checked plug behind gauge cluster. I didn’t see anything that might be a problem. Looked over wire diagram many times. When I disconnect the dk green wire that feeds power to gauge cluster lights from headlights switch ,volt gauge reads right. When sending power with the dimmer volt gauge goes to zero. I’m thinking the printed circuit is grounding. Can that be replaced. Thx

Sep 22, 2023 | 06:03 PM

ole softai

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From: Ponchatoula la

Got it

Hope this may help someone in the future. After chasing my tail I changed the printed circuit board. No luck. Lots of trouble shooting and found the volt gauge itself was grounding to cluster housing. Just a little. Used liquid tape to make a gasket on back of volt gauge. That gauge is 1 year old. If it acts up again I’ll replace it again. Learned a lot about my c3

Oct 11, 2023 | 03:31 PM

RubbaBizkit

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From: Anderson SC

Hi ole softai -

Hey your issue sounds very similar to mine => https://www.corvetteforum.com/forums...auges-off.html

You think I might have the same ground-short as you? You have any schematics to share?

Thx