Battery Light and Warning

[RCM826]

Periodically my 05 Silverado flashes a red battery warning light and a "Service Charging System" warning displays. The voltage then begins to fluctuate maybe 2-3 volts over and under 14v. Lights dim and brighten. Then warnings shut off and all is back to normal. This happens at least once a day or so for about a year. Hasn't gotten worse....any idea what problem is?

[RCM826]

The Rob. I'm on a budget. I'm ordering an OBD2 scanner from Amazon. I'm hoping I can clear it that way. I have a check engine light on as well. Evap solenoid is causing it.

*The Rob

Gahhhhhh!!! *thx Rob

[RCM826]

I've taken it to Auto Zone twice to test the battery and alternator. Both time the guy said both were operating fine.

[MikeNH]

The tester autozone and the like use is garbage and the results are often meaningless. It doesn't actually load the charging system. Chances are your alternator is on its way out.

[gmtech4]

it has a code in the charging system,,get it scanned by a real scanner ,,,,

 

 

welcome to the site ,,,,,

[TimmyG]

Cables tight/clean?

 

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[gmtech4]

clearing it will do nothing ,here is a little diddy from the description and operation of the charging system

 

Service Charging System

The generator battery control module will send a class 2 message to the IPC
for the SERVICE CHARGING SYSTEM message to be displayed. It is commanded ON when
DTC B1390, B1488, B1492, or B1516 sets. The message is turned off when the
conditions for clearing the DTC have been met and after an ignition cycle.