All dash lights are on

[robertm55]

Hello everyone, looking for a bit of guidance here.
My 2020 gladiator has 100500. Miles on it.
I have never had any issues and replaced both batteries 11 months ago.
My jeep recently sat for about a week and a half, it was cold out, and when I went to start it, all of the warning lights came on, and it wouldn't shift out of park.(it started with zero issue).
I thought maybe it was the battery, low voltage messing with the ecm. So I ran jumper cables from my other truck to the main battery. Started again and it was fine.
Drove for a week and about 550 miles with no incident.
Then on a 200 mile drive, in cold weather it happened again.(160 miles into the trip).
I got to my destination, parked and figured the battery must have a bad cell in it.
Went next morning and replaced the battery.(under warranty)
Immediately resolved the issue.
Drove another 600 miles, over the course of multiple days, no problem.
Then today it happens again.
I drove local for about 45 minutes, was sitting idling for ten minutes and everything lit up, all systems say they need service.
The truck runs and drives, without issue. But all warnings are going off.
I don't see any damage to wiring, all fuses seem to be installed tightly.
Any ideas?
Thank you in advance
Tob

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[Charles 236]

Both batteries? The small auxiliary battery is hidden in the wheel well and is not seen and so is easy to forget about. The auxiliary battery is sometimes the cause of the main battery dying, when the auxiliary battery dies, it will discharge the main battery. Have both batteries checked by someone who knows how to test them.

 

[Lost1wing]

I second that! Maybe a poor connection was made when the Aux battery was replaced.

 

[Lunentucker]

Take the AUX battery out of the equation and see what happens.
Pull fuse F42 and remove the Aux battery ground cable, insuring that it's secured and insulated from making incidental contact.

 

[Mr._Bill]

Hello everyone, looking for a bit of guidance here.
My 2020 gladiator has 100500. Miles on it.
I have never had any issues and replaced both batteries 11 months ago.
My jeep recently sat for about a week and a half, it was cold out, and when I went to start it, all of the warning lights came on, and it wouldn't shift out of park.(it started with zero issue).
I thought maybe it was the battery, low voltage messing with the ecm. So I ran jumper cables from my other truck to the main battery. Started again and it was fine.
Drove for a week and about 550 miles with no incident.
Then on a 200 mile drive, in cold weather it happened again.(160 miles into the trip).
I got to my destination, parked and figured the battery must have a bad cell in it.
Went next morning and replaced the battery.(under warranty)
Immediately resolved the issue.
Drove another 600 miles, over the course of multiple days, no problem.
Then today it happens again.
I drove local for about 45 minutes, was sitting idling for ten minutes and everything lit up, all systems say they need service.
The truck runs and drives, without issue. But all warnings are going off.
I don't see any damage to wiring, all fuses seem to be installed tightly.
Any ideas?
Thank you in advance
Tob

You had the 11 month old main battery replaced under warranty. It appears that the Aux battery is also faulty. The computers acting strange is an indicator that the voltage is too low and there are issues with the batteries and possibly the alternator.

 

[ShadowsPapa]

and possibly the alternator.

That part is doubtful due to the way this monitors the charging system.
OF course he can switch to the cluster display showing the truck's systems and look for the voltage when it's running.
I would concur with the thought of the aux battery needing to be checked out.

 

[robertm55]

I thought the auxiliary battery was just used for starter.
When the jeep had a dead battery and I couldn't jump start it last year, I replaced the battery, only to find out it still wouldn't start due to the auxiliary battery.(I didn't know it had the second battery). So replaced that and it was good to go.
The dash shows battery is charging normal.
Last night and today it has been fine, all lights are off again.

 

[Lunentucker]

There. It's fixed!

 

[ShadowsPapa]

I thought the auxiliary battery was just used for starter.
When the jeep had a dead battery and I couldn't jump start it last year, I replaced the battery, only to find out it still wouldn't start due to the auxiliary battery.(I didn't know it had the second battery). So replaced that and it was good to go.
The dash shows battery is charging normal.
Last night and today it has been fine, all lights are off again.

Yeah, the aux battery is used for the cabin electronics and other electronics (and HVAC fan ad so on) when the engine is off for the auto stop.
The main battery is what cranks the engine.
That's why the aux battery is so much smaller - it's never really called upon for a large "draw" or load in amps. And - they are connected together most of the time anyway.

I think for the most part even the "techs" in the shop don't fully understand these things. Scary.....

 

[Osteodoc08]

Wait. Did we all miss the part where he has over 100k miles?!

Hope your issues are quickly resolved.

 

[Escape.idiocracy]

That part is doubtful due to the way this monitors the charging system.
OF course he can switch to the cluster display showing the truck's systems and look for the voltage when it's running.
I would concur with the thought of the aux battery needing to be checked out.

Not arguing… not saying your wrong. Just adding to the brainstorm…. I was leaning to bad alternator too- would want to know what the voltage has been sitting at while driving. - you know is the voltage regulator shot?

Whats your theory on two batteries going out within a short period then?? What would you troubleshoot next?
Asking for my own knowledge and process of elimination when troubleshooting…

Edit- ok so just read your other post… looks like you think the small battery is the culprit.
With that theory, the small battery being bad is causing the large battery to fail- correct? I could agree with that ???- man from what I have read, I’m just going to replace both batteries at the same time when one starts to fail…..

 

[ShadowsPapa]

man from what I have read, I’m just going to replace both batteries at the same time when one starts to fail…..

From what I've seen, that's the way to go.....

I was leaning to bad alternator too- would want to know what the voltage has been sitting at while driving. - you know is the voltage regulator shot?

Voltage is regulated by the PCM - they started that back in the 90s. It regulates voltage based on engine load, battery temperature, battery state of charge (although they only monitor the crank battery), and other factors. If regulation goes bad, it gets serious.
If there is a charging system issue such as a bad alternator or output that doesn't meet what the PCM expects based on the field current, the battery light will come on. Battery light is a charging system issue.

Whats your theory on two batteries going out within a short period then?? What would you troubleshoot next?
Asking for my own knowledge and process of elimination when troubleshooting…

If it was my truck, I would:

Take the cables off the crank battery negative post,
Remove the IBS and set it aside - that will reset it
Split the negative cables so that the aux battery negative is no longer connected to the other, which isolates it from ground,
Charge the main/crank battery with a good charger capable of AGM charging and let it run a full cycle until fully charged/completed
Charge the aux battery (connect to positive on main battery and the negative cable that goes down to the aux battery) using a charger that's AGM capable. Same thing - let it run until fully completed.
I'd check the voltage on both batteries after charging, and put it all back together.
This way the IBS is reset and put on fully charged batteries.
I'd make sure that there were no (aftermarket) accessories that could be leading to larger than normal parasitic drain.

 

[ShadowsPapa]

Wait. Did we all miss the part where he has over 100k miles?!

Hope your issues are quickly resolved.

A 2020 is on the edge of needing new batteries - regardless of miles. 3 years seems to be typical for these, especially with the heat that's so close to them.
Frankly, MORE miles usually means the batteries get charged fully and the truck sits very little.
If he said "I have 10,500 miles" I'd have immediately thought - that's a really hard life for batteries. Infrequent use, sitting for long periods and/or very short drives.

The batteries in my wife's Jeeps are destined to not live very long because she averages about 375 miles a month on hers. I expect to be needing to replace the batteries in another year.
I'm thinking REALLY strongly about buying yet another battery tender and finding a way to rig it so that she can simply get in and drive away and not worry about a connection. She's not tech savvy - and she'd never deal with having to unplug anything every time she wanted to drive it.
Once she's back from her quilt retreat next weekend, I figure her Jeep will sit another week. Today it got driven only because I suggested we take it instead of mine - otherwise, it has been sitting most of this past week.

 

[robertm55]

So update,
I replaced aux battery.
Still have the issue.
Seems to happen more when it's cold out, today 60 no issues.
I just dropped it off at the stealership, see what they find.

Thank you all for advice/input.
It's much appreciated.
I will update when I find what the issue is.

 

[Hootbro]

I think you are going to have a ground issue when all said and done.

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