I have a 2007 3500 with the 6.7 Cummins. Got up one morning, about 24°F, on a fishing trip and batteries wouldn't even click the starter. Got a jump and went to a Les Schwab store to get them replaced. Should of seen the look on the guys face when I said "You'd expect stock batteries to last more than 12 years." He said "Batteries don't last much over 5 years." They were stock in my rig set up for camper use.