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There is a very good chance that the alternator has gone bad. You can check it by starting the vehicle, (if it will start), and disconnecting the neg, side of the battery. If the engine dies when the battery is disconnected, the alternator is not charging, and will require replacement. If it stays running, then the alternator is charging, and there is a connection that is bad, and requires some further troubleshooting. Check all connections first, then try the test. It is quik, and easy to do, and requires nothing special.