"16 Ram 6.7 returned towing from Florida. Unhooked, Parked in the garage and a few days later I was going to go for an oil change and it won't start. All it does is click. I have power and the batteri...
Had this happen on my brand new F350. Dealership said the batteries were fine but when I isolated them individually, one was actually bad. You can't get a good test unless they are isolated. And if there isn't enough amps the ECM will not allow it to start. In my case the brand new batteries were leaking and it was a known defect. But your batts are old enough to probably just be worn out.