Check the connector that plugs into the alternator Chris. Like I said earlier on my way back from TN my battery light did the same thing. I pulled over and cleaned the battery clamps and posts. All set. Drove approx another 50 miles and the same thing happened. We pulled over again thinking that I needed to get batteries after the alternator incident, it turned out that upon wiggling the connector the voltage would jump from anywhere from 12.1 to 14.2 volts. I ty wrapped the cable to take any pressure off the connector and it has been fine ever since.