Low battery voltage

1983 BUICK LESABRE
17,000 MILES • 4.8L • V8 • 2WD • AUTOMATIC
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WILLIAM DIAL
  • MEMBER
  • 1 POST
I have new alternator and battery but only have 12.6 at the battery with car running and when I idle the car up it starts taking the voltage down but can take the battery terminals completely off of the battery and the car stays running.
Feb 3, 2020 at 10:42 PM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good morning,

Removing the cables while running tests nothing. You most likely damaged the alternator by doing that.

I attached a wiring diagram for you. Make sure the 2 red wires have power in the on position. The other wire needs power as well.

Verify with a voltmeter.

Roy
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Feb 3, 2020 at 11:31 PM
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