Battery Light On?

Hello everyone, new to the site and not sure if anyone has experienced this or can help at all. I have a 2012 6.7 at 50,000 miles with the single heavy duty alternator.. Noticed the battery light on my instrument cluster yesterday. Checked the batteries and got 12.6 v with the engine off and 13.7 volts with the engine running. Batteries are 2 year old Napa Legends and tested 12.6 v each when I disconnected them, so they seem to be okay... (I haven't had them load tested yet though) Checked for loose or faulty connections with no visible signs from the alternator to the battery, and ground connections seem okay as well.

It's not throwing any codes just the battery light after about 20-30 seconds after start up, has anyone experienced this and have any suggestions by chance? Could it be a wire from the pcm to the alternator I should be checking or perhaps fuses??
Any info is greatly appreciated..

I'd load test the Batteries before anything else.


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Mine was doing the same thing but I had a code, p0602. I ended up replacing the alternator and it fixed the problem.

Check the wiring harness where it runs down the motor on one side, under the crank and back up...very common for the GENMON and/or GENCMD circuit wires to break in there....easiest way would be to overlay a wire from connector on alternator to PCM connector.