i have an 07 Chevy duramax. 170 k mile. Original owner. very nice clean truck. Pretty much trouble free all its life. I parked it a couple days ago in my driveway. The overnight temp was 28° here in Nashville. When I went out to start it starter would engage make a clicking attempt to turn the engine but that’s it. Pretty much just like it had a discharge battery. So I disconnected the batteries and checked them each individually and they were both at 12 9 V. I also check the starter relay and it wasn’t that. So before I start thinking about replacing the starter what should I do? I was a technician for 33 years but that was about 20 years ago but I still work on all my own stuff so appreciate your help thank you. jim