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Need some help troubleshooting charging alt system

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Old May 15, 2012 | 12:31 AM
  #1  
OutlawPerforman's Avatar
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Joined: May 2011
Posts: 75
From: san antonio Texas
Need some help troubleshooting charging alt system

A week ago I got into my car to go to work and battery was dead, so I took to autozone and they tested it and I had to get it replaced. For a week everything was great the a/c seemed to blow colder etc.

Then Friday I driving home and my lights are really dim, I had to leave it Saturday so it didn't get started all day.

So Sunday battery is dead again, I jumped it and the volt gauge only goes up to about 9 volts. The battery was tested and fine,

All signs seem to point to the alternator but I really wanna troubleshoot all other things before I pull it off and have it tested. So if you guys can think of anything or have experienced this issue lmk it would be great.

Im trying to avoid pulling alt bc I have a bad neck and to get under it wouldn't help but ill do it.
Old May 29, 2012 | 05:33 PM
  #2  
pkincy's Avatar
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Joined: Jun 2002
Posts: 113
From: Scottsdale, Arizona
Re: Need some help troubleshooting charging alt system

Either a bad alternator or a short somewhere.

Have Autozone test the alternator while it is running and while it is not.

Or if you have a Multimeter do so yourself.

You should see about 13.8-14.2 volts across it while it is running.

To check for a short remove the negative battery cable and check for current flow between the positive terminal of the battery and a ground on the engine or in the engine compartment. Current means a short somewhere in the car is draining the battery. BTW, extremely small amounts of current are OK.

Perry
Old Jun 5, 2012 | 04:30 PM
  #3  
rv93's Avatar
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Joined: Oct 2010
Posts: 563
From: West Lafayette, IN
Re: Need some help troubleshooting charging alt system

you might just have a weak alternator. happened on my first car, and the shop was sure it was the battery, and pretty much refused to replace the alternator. the way i tasted for it was basically a load test. start the car, and turn every electrical thing that you can off, and measure the voltage. it should be in the high 13s, maybe low 14s. then turn everything on. lights, blower, radio, etc, and measure again. with a healthy alternator, youll see a 0.1-0.2v drop. with a weak one, youll see a massive drop. with mine, it put out right around 14v with no load, and dropped to 11v afterwards. hope this helped, and good luck
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