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battery/alternator troubleshoot please 850

hello all,
In the past two years, I have changed 4 batteries, since each of them just last about 6 to 8 months and it died. I already checked the following items:

1. glove box light is off when the door is closed.
2. alternator output is about 13.7V
3. the charging current (measured between the alternator lead and the + battery lead when the engine is running) is about 2A @ 2500 rpm.

Does it sound like the alternator is bad?

thanks,

Cheng








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    battery/alternator troubleshoot please 850

    <>
    Yes, definately. Have it tested at an auto parts shop. I just replaced the one on my 96 (6 mo. ago now) and it solved my dead battery problems. The voltage reading (13.7V) is not a good indicator of how much current the alternator is putting out. It is a 100A alternator and mine measured 45A max. That is an indicator that it was shot.
    I got my replacement at Auto Zone (rebuild). Tedious job, but I have done worse.
    Good Luck,
    --
    Tom 69-1800S, 72-1800ES, 96-850T,2000-S70 GLT-SE








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      battery/alternator troubleshoot please 850

      It is true you should have the maximum output measured with an ammeter. However the alternator output can be checked indirectly by measuring the voltage first with the engine running and a light elecrical load (all accessories and lights off) then with a heavy load (turn on most or all of the accessories and the high beams). At about 2000 rpm, whatever the voltage is with minimal load should be maintained quite closely with the heavy load. If it drops more than 0.1 - 0.15 volt or fluctuates then one or two of the alternator's 3 phases may not be working. I would do these measurements right at the battery terminals since that is where solid current needs to be delivered.

      Another possibility is that the brushes are worn or dirty or less likely a bad regulator.

      The figure of 13.7 volts is probably reasonable in warm weather. In a cold winter it should be 14.2 or more.








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      battery/alternator troubleshoot please 850

      Tom, thanks for the comment. I have been reading about how to replace the alternator on the internet. So, is it necessary to remove the power steering pump in order to access to the alternator? Any tip or comment will be appreciated.
      thanks,
      Cheng








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        battery/alternator troubleshoot please 850

        I recently had the unfortunate experience of removing/installing multiple alts. in order to get a good one. It's not an easy job. I did drain the coolant, remove the upper radiator hose, removed the plastic box & cpu boards across from the PS pump, and then the PS pump. You don't need to drain the PS reservoir, just move it out of the way.

        You'll have to be the judge of your own mechanical ability.

        Good Luck!








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          battery/alternator troubleshoot please 850

          I just finished removing the shims in the ac compressor and had to remove the alternator to get to it adequately. I didn't remove the CPU box. Instead I ran a ratchet strap from the driver's wheel to the upper motormount and put a little pressure on to allow room for the ratchet. ( My lower mounts need to be replaced so the engine is shifted right a couple of inches.)

          I did find it much easier to work with the fan removed. I didn't remove the radiator hose but it would have been easier to get the power steering pump out of the way if I had.

          Good Luck.







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