Normal charging for your vehicle from the GM Repair Manual is 13.8 to 15.5 volts.
This depends on load, temp, battery charge, current sensor on the neg cable, BCM, etc etc.
If you suspect a bad alternator, increase the load by turning on headlights, A/C fan on high, power windows, etc and watch your voltmeter.
A bad alternator is a possibility and probably a good place to start, it could be wiring, BCM, battery current sensor, battery cables, serpentine belt or another thing.
This depends on load, temp, battery charge, current sensor on the neg cable, BCM, etc etc.
If you suspect a bad alternator, increase the load by turning on headlights, A/C fan on high, power windows, etc and watch your voltmeter.
A bad alternator is a possibility and probably a good place to start, it could be wiring, BCM, battery current sensor, battery cables, serpentine belt or another thing.