Ram 6.7 no start

Presuming not original batteries? If OE batteries they are likely toast. 1 of them anyway. Maybe even replacements could be done for, just not as likely.
How did you “check” them? If one is bad and the other still good you’ll get a “good” reading, if you didn’t isolate them.

Several questions:

So you say it won't start than you say all it does is click.
So no crank, no start? (This is important) Big difference between no start and no crank, no start.

You state the batteries checked ok? How were they checked? With a VOM or with something that can put a load on them?

Are they the original batteries?

Have the battery connections been checked?

No crank, no start, 98% of the time it's going to be batteries, connections or starter. Someone is going to have to figure out which one of the 3 is causing you problems. Let us know what you find.

It only clicks one time. Battery connections are good . Checked batteries with volt meter. Original batteries, 48000 miles. Why would it go dead right away if it was batteries ?

If you boost it and it starts it’s the batteries.

M.R.E. wrote:
It only clicks one time. Battery connections are good . Checked batteries with volt meter. Original batteries, 48000 miles. Why would it go dead right away if it was batteries ?

Because that’s what they do. One or both get weaker until the ECM shuts it down. It won’t just crank “slow” if weak batteries, like an old car.
If you’re observant, you likely felt it cranking a “bit” slower but otherwise unaffected.
Original 7-8 year old batteries and especially not driven much…it’s your batteries.

Original 100k mile 2016 Ram batteries. Few months ago, knew they were weak. Somehow they made it thru a short winter trip with below zero AM cold starts.
Bout 3 days after returning to warmer weather they still worked and then no worky the next morning.
Fwiw I found a great price on Delco AGMs on Amazon iirc. But whatever, you need batteries. And that’s all.

womps wrote:
If you boost it and it starts it’s the batteries.

Yeah if you’re not diy or don’t have another car, it’ll run if you jump start it. Just don’t turn it off until you have the new batteries or ability to jump it again.

M.R.E. wrote:
It only clicks one time. Battery connections are good . Checked batteries with volt meter. Original batteries, 48000 miles. Why would it go dead right away if it was batteries ?

Your 7 YO batteries are toast IMHO. The only true way to tell is with a mechanical load tester or electronic load tester.

The last 4 batteries I have bought for my truck were good one day and bad the next. One time caught me on vacation. :o They used to give you warning but not the batteries of today or the trucks of today. I "think" it's because of the duel batteries in the trucks I have?

BTW I just replaced a 5 month old battery at work. NCNS. Battery dead flat. I charged it up to 12.7 Volts. I thought oh, that's good. Then I did my due diligence and it failed miserably under an electronic load test.

I'm with turtle. I think your batteries are done. I have a 2015 with the 6.7 and my batteries went out about this time last year. These engines require a good amount of current to push them, especially if its a little chilly out. Try jumping from another truck and seeing if it starts. That way you'll know for sure... but I'd bet $1 its a battery.

Turtle n Peeps wrote:

M.R.E. wrote:
It only clicks one time. Battery connections are good . Checked batteries with volt meter. Original batteries, 48000 miles. Why would it go dead right away if it was batteries ?

Your 7 YO batteries are toast IMHO. The only true way to tell is with a mechanical load tester or electronic load tester.

The last 4 batteries I have bought for my truck were good one day and bad the next. One time caught me on vacation. :o They used to give you warning but not the batteries of today or the trucks of today. I "think" it's because of the duel batteries in the trucks I have?

BTW I just replaced a 5 month old battery at work. NCNS. Battery dead flat. I charged it up to 12.7 Volts. I thought oh, that's good. Then I did my due diligence and it failed miserably under an electronic load test.

This is good advice...

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.