1997 Chevy Suburban Battery voltage drops

1997 CHEVROLET SUBURBAN
170,000 MILES • V8 • 2WD • AUTOMATIC
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when i have both the front and rear ac on at full blast and the truck is not moving but in gear, the battery voltage begins to drop. i have already replaced the alternator and it didn't help. any ideas?
May 18, 2010 at 4:47 PM
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MHPAUTOS
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Hi there,

What is the alternator out put readings when you do this? and is the idle a bit low and the alternator has not kicked in ?

mark (mhpautos)
May 18, 2010 at 5:18 PM
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Thanks for your response, i don't know how to check the output reading for the alternator and what would you consider too low for idling, thanks for your help
May 18, 2010 at 5:43 PM
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MHPAUTOS
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Place a volt mete r(+) on the alternator output terminal(large terminal) and neg (-) on to battery earth, idle the engine and take a reading you will want about 13.5 V there abouts, what do you have.

mark
May 18, 2010 at 6:04 PM