Puzzled Truck Won't Start

[dcmdon]

If you are under 11 volts after having the battery on a charger. Its gone. Done. Kaput.

Absolutely no doubt.

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[Maximus Gladius]

Your charger needs to be AGM compatible too

 

[Rusty PW]

Like others have said. 10.3 volts with a AGM battery. It's dead. Best to replace both batteries.

 

[BAT]

So the latest and greatest on this puzzling thing. I borrowed another charger that was fancier and I suspect it may have been more compatible as mentioned in the comments. After being on the charger all day today the battery is back up to 14.3 capacity and has stayed that way for the last 3 or so hours. I drove it around a bit and then parked it and let it sit in the same setup and situation as the previous night. After just checking it again a few minutes ago it is still cranking back up with no issue and holding 14.3. Pressing in the break is easy to do now also as it seems like it kind of just-released all its tension after the battery came back up to charge. I am still not quite comfortable just yet with it so will let it sit all night and then see it again in the morning. I might drive it to the dealership just to chat with them a bit see what they say. Still so strange it just went dead. I have removed the Tazer currently but I had the Tazer on basically since I bought the truck so can't really see that being a factor.

 

[BAT]

Your charger needs to be AGM compatible too

I borrowed a different charger which seems to have worked in getting the battery charged up.

 

[BAT]

Forgot I am now getting a message that my AUX switches not functioning due to battery charging but the battery is not charging for some time and the AUX switches work fine.

 

[kooltoys]

only hope, disconnect both neg terminals. connect a good battery inline with 1 of the neg cables. charge to full.. then do the same with the second battery.. 3rd charge both neg terminals seperate to full charge.. either 1 or both batteries will not take charge and dissipate rapidly.. best way to troubleshoot at home

 

[BAT]

Still holding 14.3 this morning but the radio cut on and off about 3 times after I started it up this morning and still getting message that the Aux Switches temporarily unavailable

 

[BAT]

So the final chapter on this after I got my truck back from dealership and them checking it out. They concluded that the Auto Start/Stop Battery died and then took down everything else. They said that they tested the main battery and it was testing fine. So they replaced the Auxilary battery, updated everything and returned the truck to me. So guess we will just hope that all is fine.

 

[ShadowsPapa]

I always found the simplest answer is usually correct One from time to time I have this problem and and it is usually that the brake pedal is hard to push due to loss of vacuum and with a little gorilla force on the brakes while pushing the start button it works have also heard of the switch on the brake pedal going bad. A bad battery will usually at least click the starter also does your key fob work to open the door?

Actually a low battery on these won't because the system shuts things down. You don't get the click like the old Fords used to do. If certain voltage requirements are not met, the relay for the starter circuit is not triggered, no click, no nothing. This can even happen above 10 volts. Went through it on my wife's Jeep.

Don't get distracted by the brake pedal thing if the voltage is THAT low.

Nissan tells dealership shops that if an AGM battery is under 12 volts, don't give it to the customer, replace it.


This is for a different make vehicle, not Jeep, but what it's saying is that if the voltage is too low, it doesn't allow things to wake up......

• When ”terminal 15 OFF” has been received, the DME / DDE informs the IBS of the maximum battery charge quantity available.
• After issuing the message about the maximum charge quantity available, the DME / DDE will go into sleep mode.
• If the maximum battery charge quantity available has been reached and auxiliary consumers are switched on, the IBS will ”wake up” the vehicle (and thus the DME / DDE) via the wake-up wire (terminal 15 wake-up).
• When the battery's critical charge state has been reached (battery's limit of starting capability), the DME / DDE instructs the auxiliary consumers to switch themselves off.
• The DME / DDE no longer allows the IBS to ”wake up” the vehicle.

 

[jebiruph]

Usually when the aux battery runs down it takes the main battery with it, unless the ESS (N3) fuse is blown. It might be worth checking that fuse, if it is blown the aux battery will go dead again. Here's some information about it https://www.jeepgladiatorforum.com/forum/threads/ess-dual-battery-system-operation.44028/post-709139

 

[ShadowsPapa]

Usually when the aux battery runs down it takes the main battery with it, unless the ESS (N3) fuse is blown. It might be worth checking that fuse, if it is blown the aux battery will go dead again. Here's some information about it https://www.jeepgladiatorforum.com/forum/threads/ess-dual-battery-system-operation.44028/post-709139

The AUX battery charges through that high-current fuse, does it not? So if blown, it won't charge.

 

[Rvalas]

I am sure this has been linked a hundred times in a hundred different threads but here it is again, best purchase IMO. FCA should do away with the lawn equipment battery and just do it right.

https://www.genesisoffroad.com/jt-dual-battery-kit

 

[jebiruph]

The AUX battery charges through that high-current fuse, does it not? So if blown, it won't charge.

Exactly. There's usually enough of a charge in the new battery to last a few days and then it dies again. The symptoms described here are a good match for a blown ESS fuse, I think it's worth checking.

 

[BAT]

Exactly. There's usually enough of a charge in the new battery to last a few days and then it dies again. The symptoms described here are a good match for a blown ESS fuse, I think it's worth checking.

I'll give it a look as a back up to their diagnostics but basically yep the ESS went down and then it took the main battery down as well.

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