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When I take one of my battery post off the battery while its running, the vehicle shuts off, what is it?

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Apparently the alternator is not working. Jerry, you should never take the battery post off a running car. Used to be okay to test the alternator that way, but that was before computers and modern electronics. Nowadays, you can easily fry computers, alternators, and other electronic components by doing so-not always, but always that chance. Disconnecting the battery even with just the key on, causes voltage spikes in circuits- very harmful to computer circuits that are low current. About the only way to test circuits is with a multi-meter. The best automotive multi-meter is a digital volt ohm meter (DVOM), and you can find them very reasonable at Sears, auto parts stores-anywhere.
So the alternator is not working... to continue: when the engine is running, all power to run all electrical circuits on the car is supplied by the alternator. Battery is tied in with the alternator, but no power comes out of the battery-it is being recharged by the alt.-recharged for it's next use of giving its all to the starter motor to start the car.

Test everything before condemning the alternator-could be something else not letting it work- Testing is the cheapest method to find the problem.

Posted on Dec 25, 2013

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On older cars, that's an indicator that you need an alternator. Have it checked though because newer cars rely on a direct 12v from battery for the pcm's keep alive memory function

Posted on Dec 25, 2013

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Altenator check for power on back of it if power replace alt

Posted on Dec 25, 2013

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