Little wire on the alternator.
Little wire on the alternator. 
Its called the exciter wire and the alternator wont charge if its not connected. It is easy to rip the wire from the connector, but if you rip it out you can buy a new connector with the wire from the dealer.
You can follow it down from the top of the engine to the top of the alternator...with my AIR system out of the way (and probably even with it in the way), I can disconnect it standing over the driver's side front fender. Very important, VERY small wire.
