Question about 1988 Chevrolet Suburban

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Alternator won't charge consistently on 1988 GMC suburban

Voltmeter shows alternator putting out a charge when vehicle is idling. The voltmeter will continue to show and increase in voltage. once the voltmeter shows a significant charge, I can begin driving and turn on all electrical devices, heater fan, lights, radio, back window, etc. However, as soon as I brake or let my rpms drop off, the voltmeter shows that I am draining the battery. If I stop, let it idle, it will build back up and I can go again with everyting on.

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Fake it off and have it checked for free at auto zone, it sounds like your voltage regulator is shorting out

Posted on Mar 09, 2009

  • Dennis Mulford
    Dennis Mulford Mar 09, 2009

    take it off and have it checked for free at auto zone, it sounds like your voltage regulator is shorting out

  • Dennis Mulford
    Dennis Mulford Mar 09, 2009

    take it off and have it checked for free at auto zone, it sounds like your voltage regulator is shorting out


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Hi there
it sounds like you have a bad diode in the alternator

and since the voltage regulator is internal you will have to replace it or take it out to get tested
thanks you

Posted on Mar 09, 2009


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