Electrical help needed ASAP??

[SIxSixRider]

Got in my ‘21 JL (3.6L) this morning & it was TOTALLY dead. It started with a jump but radio display is blank. All other controls seem to work. The speedo display shows ~13.4-13.5V while running. I don’t recall leaving anything on that might’ve discharged the battery overnight. The guy at a local AutoZone suggested it should read closer to 14V while being charged by the alternator…bad alternator? A new battery would be an easy fix but could also be a waste of money if it’s the alternator (or something else). I’m traveling (towing Jeep) so resources are limited & I’m >800miles from home. Any troubleshooting input would be appreciated.

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[jeepingib]

Got in my ‘21 JL (3.6L) this morning & it was TOTALLY dead. It started with a jump but radio display is blank. All other controls seem to work. The speedo display shows ~13.4-13.5V while running. I don’t recall leaving anything on that might’ve discharged the battery overnight. The guy at a local AutoZone suggested it should read closer to 14V while being charged by the alternator…bad alternator? A new battery would be an easy fix but could also be a waste of money if it’s the alternator (or something else). I’m traveling (towing Jeep) so resources are limited & I’m >800miles from home. Any troubleshooting input would be appreciated.

Do you have a separate ess battery underneath the main battery? If so, then that is likely the culprit.

 

[SIxSixRider]

Do you have a separate ess battery underneath the main battery? If so, then that is likely the culprit.

To be honest, I’m not sure. I’ve never had the main or aux factory battery out…no reason to. I was just watching a few videos showing where the aux battery is & how to replace it.

 

[jeepingib]

That's likely the problem. There are some good guides in here about how to bypass it. Funky voltage plays hell on canbus systems. So it can cause the issues you described. And the little one can drain the main battery and kill it.

 

[CaJLMetalHead]

To be honest, I’m not sure. I’ve never had the main or aux factory battery out…no reason to. I was just watching a few videos showing where the aux battery is & how to replace it.

Is your E-torque?... I think the e-torque versions do not have an AUX battery...

if yours is the one with dual battery... I suggest you disconnect that pesky AUX battery and run with a main battery only.. like thousand of Us do ... that AUX battery is nothing but trouble..

 

[Steph1]

Start by opening the hood and make sure all fuses are pressed-in all the way.

 

[GATORB8]

Flat towing? If you are harnessed, I know there are issues with the Jeep going to sleep. Look at those threads.

 

[mgarciaknight]

JL or JLU?

 

[SIxSixRider]

UPDATE & to answer some questions: YES it has eTorque. It is a JLUS. And YES I flat tow but I drove it yesterday (after towing the day before) and my tow setup uses an air braking system - NO power from the Jeep.

After jump-starting it, I drove it on a few short errands (maybe 20min driving time) and shut it off when I got back. It sat for maybe 15-30min. I started it again (no need to jump it) and the radio display was working fine.

At this point I’m suspecting the charge put on the battery is allowing everything to work. The question is: For how long? And I’m still not sure if I’ve got an AUX battery under the fuse box since I’ve got eTorque.

 

[mgarciaknight]

The 3.6 e-torque DOES NOT have an AUX battery.

 

[Zandcwhite]

It also doesn’t have an alternator. You could pull the battery and have it load tested at auto zone if issues persist. The 12V battery is not covered by warranty and replacing it will be cheaper than having the dealer diagnose. Anything else in the etorque charging system is covered by 8 year/80k mile warranty as it is considered emissions equipment.

 

[SIxSixRider]

Sounds like I either unknowingly left something on that killed the battery or the (main) battery is going bad. What about the ~13.5V reading while running? Normal? Low? Just trying to rule-out a potential alternator/charging system issue.

 

[Zandcwhite]

Sounds like I either unknowingly left something on that killed the battery or the (main) battery is going bad. What about the ~13.5V reading while running? Normal? Low? Just trying to rule-out a potential alternator/charging system issue.

The etorque belt start generator tends to settle in the mid 13s when running.

 

[dragoneggs]

This has happened to me twice in the year plus that I have had my 3.6eTorque. Haven’t figured out why it happened but I am guessing that I accidentally left the ignition in the accessory position instead of off. Now I am very conscious that it is indeed in the off position when I exit.

 

[SIxSixRider]

This has happened to me twice in the year plus that I have had my 3.6eTorque. Haven’t figured out why it happened but I am guessing that I accidentally left the ignition in the accessory position instead of off. Now I am very conscious that it is indeed in the off position when I exit.

It’s certainly POSSIBLE I left something on too. I bought a 12V jumping pack today to carry with me so I don’t get stranded and I’ll see how she behaves going forward.

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