my battery light comes on i can rev the motor and it will go out?

2004 GMC CANYON
239,000 MILES
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my battery light comes on i can rev the motor and it will go out . i checked voltage at battery when light is on 11.9 volts rev engine light goes out and stays out with 14 volts what is my problem
Jan 14, 2013 at 1:56 PM
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KASEKENNY
  • ✓ASE Certified Mechanic
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More than likely you have an alternator that is failing. This means we need to test the alternator and it sounds like you already have but here are a couple guides that will help with this:

https://youtu.be/Z-p4dMJUpUw

https://www.2carpros.com/articles/how-to-check-a-car-alternator

https://www.2carpros.com/articles/how-to-replace-an-alternator

I am attaching the process below on how to replace the alternator as I suspect this is the issue.

Please run through this and let me know what you find. Thanks
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Dec 28, 2021 at 5:00 PM
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