Chevy Alternator Not Charging | race-deZert May 16, 2010Fat wire from heavy lug on the back of the alternator is the output wire. My guess is that this is the wire that is broken, and it is most likely the fuse link that is at the far end of that wire. Now the two wires on the connector - there is a thin wire that is your excite wire. It is a resistor wire.Alternator at 15 volts ok? | race-deZertApr 26, 2010Big Alternator | race-deZertAug 28, 2007Alternator Issues | race-deZertNov 09, 2005Charging System Help | race-deZertNov 06, 2003See more results Alternator Not Charging: Alternator Not Charging. Changed Alternator not charging. Changed alternator with no change. A+ wire to alternator reads 12 with key off. After starting engine, voltage went down to 6V.