I have an 07 NNBS Silverado and I've been getting the "Service Battery Charging System" message on the dash along with the battery light. At first, it happened every so often and the light would go away after a few mins of driving. Now, most recently, its been more consistent and the light has been on longer. I've done tests on the alternator and battery-no issues. Voltage meter stays around 14, never drops significantly, and everything inside and outside work just fine. No dimming of the dash lights, headlights, and radio has no issues working.
I have absolutely no idea how to fix this and I'd rather not have to take it to the dealer if all possible.
Any help would be greatly appreciated!

To solve the mystery without a parts cannon, you need a bi-directional scan tool that can pull the internal codes that are triggering the light. If the voltage does not drop, then EPM/RVC is not working properly, probably because the alternator is not putting out the juice necessary to keep the battery charged. Check your grounds and battery cables, make sure the connector on the negative battery cable, right off of the battery is connected.

 

Thank you, I will check the cables again and see if there are any loose ones. My cables/terminals are cleaned and I know for sure the cables aren't loose on the battery. I unfortunately can't afford a bi-directional scan tool. Might have to see if a friend has one.

 

^^^^ this. That's where I would start, checking/cleaning/repairing all grounds and maybe testing/replacing both battery cables.

 

The cables can look good but be corroded under the sheathing.

 

Get a knockoff or used techii, it should work for your truck, and can do the job. If you plan on keeping your vehicle for some time, and working or at least diagnosing problems yourself, it really helps. Without good diagnosis tool, your left with the parts cannon, which also isn't cheap.

 

In a 2007, your voltage meter should actually drop well below 14V. Starting in 2005 the voltage is controlled by is it the BCM? Voltage dropping to 11V is regular, and in the owner's manual that it is normal.

The problem is actually that your voltage is NOT dropping.

 

This is good to know. I added the entire TP2 aux battery system to my 07 NNBS along with a digital voltmeter in the dash reading both batteries constantly. Was wondering if that drop from 14v to 11v was a sign of weakening main batt. Not. Thx