changed alternator but my battery light is still on

2001 BMW X5
310 MILES
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KELLY_FELLNER
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I have a 2001 X5 with an alternator issue... About two weeks ago with no warning the Battery light came on. I replaced the alt with a new (Wilson) one, no change!!! my question is, is it an out of box no good or is there something else that i should be looking at? Kelly
Dec 4, 2011 at 6:45 PM
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CARADIODOC
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Hello,

There are two fuses that run the system I would check there first here is a wiring diagram (below) that shows the fuses and how the system is wired.

The alternator, is just one part of the charging system. All alternators will have a wire to turn it on when the ignition switch is turned on or when the engine is running. A break in that wire will stop the system from working. A break in the wire between the output terminal and the battery will prevent it from recharging the battery but that usually won't cause the warning light to turn on. If a fuse is blown, the voltage regulator won't turn on.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (Below)

Please run some tests and get back to us.

Cheers
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Dec 4, 2011 at 7:23 PM
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KELLY_FELLNER
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All the fuses check out as and the plug for the alternator has power as well. So I got another unit and it worked it must have defective. Thanks Kelly
Dec 4, 2011 at 10:40 PM
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CARADIODOC
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Nice work, we are here to help, please use 2CarPros anytime.

Cheers
Dec 4, 2011 at 10:57 PM