ISSUE RESOLVED: Drove truck yesterday and today it won't start, need help troubleshooting

[Billet Bee]

2020 ram 3500 drw 6.7 hohd, 38* degrees last night.
Our truck has been driven every few days with zero issues, and it was drove just last night. This morning we hit the auto start button on the key fob and it never started, so went outside to check and we hadn't closed the tailgate from opening it just 30 minutes earlier ( know I didn't leave it open all night) so I knew that's why it wouldn't auto start with the fob. So slammed tailgate shut and climbed inside truck, closed door, hit start, pre heat light started doing its little countdown thing and when it got finished where the truck should of started it just did 1 click only. So i figured too low of batteries since one is 5 years old and the other is 3 years old. I checked the volt meter on the evic dashboard and it showed 12.6v, then grabbed our ohm meter and checked both batteries on their actual posts and it showed only 12.1v. I know it needs more then 12.1v to fire up so we stick our little itty bitty 6 amp charger on it and after a couple hours tried to start it and no difference except this time every warning light on the dash was flickering on and off. Another diesel pulled in and we flagged him down to jump it off and that also made zero difference. We checked every fuse pertaining to ignition systems and starter and all those mini fuses were good. The wires around the starter and sillinoid are tight, tapped on the starter and sillinoid, tried to start and still just a single click and all the warning lights started flashing . Moved the shifter through every positron and back too park and still no start. Cleaned both batteries terminals and all there connections, still no start. Took wires off of battery and let it sit for 30 minutes hoping it would reset or clear itself out, took batteries out of both fobs hoping they would clear out, still just a single click with all the flickering warning lights. Also full on fuel and all oils, and we don't hook up the engine warming plug unless it gets in the 20's.
I'm not sure what else there is to trouble shoot and before we pay hundreds of dollars to have it carried away and then to have the dealership tell us it was just this simple do ja hickey I figured I'd ask on here for help and say WTF am I missing???
Thanks for any help provided.

 

[CanuckRam1313]

While I'm no diesel expert, as you and many here know, batteries are a finicky thing with Ram's, period.

I'd start with two new fresh batteries, and perhaps also look at AGM's, too (buy once & cry once).
They are older existing batteries currently, and having two batteries that are new & fresh from the start isn't a bad thing (plus you'll have a warranty for them both as well).

 

[Billet Bee]

While I'm no diesel expert, as you and many here know, batteries are a finicky thing with Ram's, period.

I'd start with two new fresh batteries, and perhaps also look at AGM's, too (buy once & cry once).
They are older existing batteries currently, and having two batteries that are new & fresh from the start isn't a bad thing (plus you'll have a warranty for them both as well).

We're considering having an auto parts store deliver us 2 new ones, (since this is our only vehicle). Just wanted to get opinions first, any idea how many volts are needed to start the 6.7, i know it's high just don't remember the exact number?

 

[CanuckRam1313]

Look at Odyssey for the AGM's if you're going that route

 

[CanuckRam1313]

We're considering having an auto parts store deliver us 2 new ones, (since this is our only vehicle). Just wanted to get opinions first, any idea how many volts are needed to start the 6.7, i know it's high just don't remember the exact number?

 

[Daw14]

Resting voltage should be no lower than 12.6 Volts.

 

[turkeybird56]

Batteries replace both. When U said U got click in start that be a big clue especially on them big 6.7’s. All IMHO.

And do not cheap out on the batteries just saying.

 

[Billet Bee]

Look at Odyssey for the AGM's if you're going that route

Tyvm CanuckRam

 

[Billet Bee]

Batteries replace both. When U said U got click in start that be a big clue especially on them big 6.7’s. All IMHO.

And do not cheap out on the batteries just saying.

Tyvm turkeybird

 

[Billet Bee]

Batteries replace both. When U said U got click in start that be a big clue especially on them big 6.7’s. All IMHO.

And do not cheap out on the batteries just saying.

Any idea why jump starting with another diesel wouldn't do the trick?

 

[Billet Bee]

View attachment 574528

any idea why jump starting with another diesel wouldn't do the trick?

 

[Billet Bee]

Resting voltage should be no lower than 12.6 Volts.

Tyvm Daw, any idea why jump starting with another diesel wouldn't do any good

 

[CanuckRam1313]

any idea why jump starting with another diesel wouldn't do the trick?

You had indicated one battery is 5yo and the other is 3yo.

When you get the "click" upon attempted start up, that's the biggest indicator right there your battery(ies) are dying or dead...

When you checked them you had 12.1V...not enough for the Cummins to start nicely (or at all).

Jumping is a band-aid and may get you started, period.
What if a cell (or cells) is/are damaged/dead in one or both batteries?
Both are old and tested below starting specs for a Cummins diesel, especially on a cold start.

Pls consider the advice you've received and replace both batteries with top quality ones (possibly AGM if you're into that).

Then I'd be testing your charging & starting systems after the batteries replacements to ensure everything is in top condition, especially being your only vehicle!

 

[Dean2]

You tried charging the batteries and they did not take a charge. Jump starting is just a form of fast charging. If your batteries cannot accept a charge to get them up to at least 12.5, jumping won't work either.

 

[CanuckRam1313]

You tried charging the batteries and they did not take a charge. Jump starting is just a form of fast charging. If your batteries cannot accept a charge to get them up to at least 12.5, jumping won't work either.

^^^^ THIS ^^^^

 

[Daw14]

If you have dual batteries they should always be replaced in pairs.
If only one is new it will drag the other down.

 

[CanuckRam1313]

If you have dual batteries they should always be replaced in pairs.
If only one is new it will drag the other down.

^^^ THIS ^^^

 

[Billet Bee]

You had indicated one battery is 5yo and the other is 3yo.

When you get the "click" upon attempted start up, that's the biggest indicator right there your battery(ies) are dying or dead...

When you checked them you had 12.1V...not enough for the Cummins to start nicely (or at all).

Jumping is a band-aid and may get you started, period.
What if a cell (or cells) is/are damaged/dead in one or both batteries?
Both are old and tested below starting specs for a Cummins diesel, especially on a cold start.

Pls consider the advice you've received and replace both batteries with top quality ones (possibly AGM if you're into that).

Then I'd be testing your charging & starting systems after the batteries replacements to ensure everything is in top condition, especially being your only vehicle!

Ohhh we definitly will, and we're gonna find some agm's also.
Is there a particular brand you'd recommend?

 

[Billet Bee]

You tried charging the batteries and they did not take a charge. Jump starting is just a form of fast charging. If your batteries cannot accept a charge to get them up to at least 12.5, jumping won't work either.

yea they show 12.6 when a charger or another truck is ambilical corded to us, but our true resting voltage is only 12.1. It's there a specific brand of agm you'd recommend?

 

[Billet Bee]

If you have dual batteries they should always be replaced in pairs.
If only one is new it will drag the other down.

Is there a brand of agm you'd recommend?