JTSilverado

Hello, 2017 Silverado 2500HD, 6.0l, auto. Sometimes the Volt Gauge reads 11v, then by itself goes back to normal 14v reading. No other warnings on DIC or idiot lights when gauge reads 11v. I would assume the DIC would show Low Charging if the alternator was bad. Would like to fix before I get stuck somewhere on the road. Thanks in advance,