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1998 Mercury Mystique

Question: battery light on new alt

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Visitor, 2.0L 4 Cylinder, Lakemore, OH, April 22, 2011, 15:54

why would battery light be on at idle just replaced alt still dosent work battery tested good but light goes off when throttle engaged

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  • Answer #1

    patrick mannion from Greg Solow's Engine Room, April 22, 2011, 18:59
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    Sounds like an internal alternator problem or bad electrical connection. It could be a bad or unsecured battery ground cable between the battery and chassis or chassis and engine. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.

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