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Old 10-01-2009   #19
-=Jeff=-
 
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Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,161
Default Re: Alternator or Battery???

Quote:
Originally Posted by batchman View Post
How many miles on the car?

I don't know GMs charging setup but my experience has been as you run up miles, alternator brushes will wear and give less output at idle/low rpm. A car with an idiot light will show this first as a low glow at idle. The last several I've had to worry about were at 120-150k miles or so.

The other popular alt failure is in regulation, which is often integrated into the alt, which will be a sudden total failure.

Good luck,
- Jeff
63K miles
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