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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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| | | | Joined: Apr 2006 Posts: 24 Junior Member | | Junior Member Joined: Apr 2006 Posts: 24 | I know the gas gauge goes down fast enough on it's own, but what would cause it to drop 1/4 tank when I turn the headlights on? | | | | | Joined: Jun 2007 Posts: 90 Wrench Fetcher | | Wrench Fetcher Joined: Jun 2007 Posts: 90 | Usually old wiring will cause this due to the many poor connections that have built up corrosion over time. I'd suggest running a new accessory power line to the fuel gauge right from the keyswitch... assuming the keyswitch itself hasn't built up high resistance. | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | WCKaner,
I will go out on a electrical limb on this one. Does your '66 C10 have a printed circuit board dash panel...I think it does! I wonder if turning on the headlights bleeds power through one of the little dash lights and 'cornfuses' the ability of the fuel gauge to see ground and read correctly. Maybe this short is finding ground through the fuel gauge.
If you sit in the cab at night and pull on the headlights, is there a bulb in the dash that is blown out or appears weak! This could be your issue....maybe. I could get blown out of the water with this theory...lets see what happens.
EDIT. Further digging leads me to believe that your dash panel is a conventional wired system, and that I might be way out to lunch.
Stuart | | |
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