Causes and Fixes Battery Light On but Alternator is Charging 

The reasons why a charging system light can come on when the alternator test good and is charging. For More Information Read Here: www.backyardme...
Possible Causes
Alternator Low Voltage Output or Intermittent Issue
Bad Voltage Regulator
Bad Battery Sensor
Bad Battery
Bad Wiring Connections
High Amp Load
Blown Fuse
Warning Light Malfunction or Wiring to the Indicator Light.
Bad PCM/ECM
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