Nov 112016
 

2002 Chevy TrailblazerI have a battery light on and when engine is off and keys in pocket still have a dim battery light.


RESPONSE

The battery light comes on when the alternator is no longer charging the battery. An internal diode has failed inside your alternator. Replacing the alternator should take care of the battery light.

Charging System Indicators

 BATTERY

The IPC illuminates the battery indicator when the following occurs:

  • The PCM detects that the generator output is less than 11 volts or greater than 16 volts.  IPC receives a class 2 message from the PCM requesting illumination.
  • The IPC determines that the system voltage is less than 11 volts or greater than 16 volts.  IPC receives a class 2 message from the body control module (BCM) indicating the system voltage.
  • The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
  • The ignition is on, with the engine off.

BATTERY NOT CHARGING

The IPC illuminates the battery not charging indicator in the driver information center when the following occurs:

  • The PCM detects that the generator output is less than 11 volts or greater than 16 volts.  IPC receives a class 2 message from the PCM requesting illumination.
  • The IPC determines that the system voltage is less than 11 volts or greater than 16 volts.  IPC receives a class 2 message from the body control module (BCM) indicating the system voltage.

 Leave a Reply