Random Check Guage Light

[01_USACummins]

Alright guys so this morning I went out and started the truck and gave it a minute and rolled off about 3 minutes gown the road at 30mph the check Guage light came on and I looked at the dash and the volts were all the way down. I turned into a lot and shut the truck off and did a Guage function check the volt Guage worked so I just started the truck and continued my 150 mile trip this morning with no further problems. The volt Guage stayed at about 15 the entire trip. Any ideas?

[Buzzinhalfdozen]

The first thing I would do is get the charging system checked to see what it's actually charging at. 15 volts is high enough it could boil the battery.  There are a few different things that could cause this so you need verify if it's actually over/under charging.