I have a 2016 Chevy 3500 HD diesel with around 77K miles. I assume it about the same as yours?? I still have the original batteries in it. It gets driven from Alaska to Arizona and back each year. I found volt meter would stay low for a long time when it was cold, but worked fine in warm weather. I thought the batteries were bad and took it in to the dealer. Come to find out the batteries were fine, but the alternator was bad. There are some heaters that come on in colder weather that don’t in warm weather. The alternator couldn’t keep up with the heaters and camper.
The check engine light came on last October and it turned out to be the DEF heater went bad. It was fixed under warranty as it is a known problem. I assume yours will go bad sooner or later?? DEF freezes at 12* so it is important not to fill it up all the way in colder temps. You need to leave space so it can expand without breaking the tank if your heater goes out.
In Ft Nelson, BC about 3 weeks ago it came on again. It turned out to be the intake heater was bad. A couple of years ago the exhaust sensor went out. Don’t know if this happens on a regular basis or not???
I am not going to change my batteries till they go bad.
2016 3500 HD Durmax
1994 S and S 9.5' Camper (SOLD)
1999 S and S 9.5 Camper