After 4 years and 42K later ... It's time

[HendersonJL]

I started to get the ESS light to come on (and off intermittently) since Wednesday. I guess it's time to replace the aux battery. I had replaced the main battery back in December 2021 and I didn't take the advice of replacing both (i.e. aux and main batteries at the same time).

Some of the aux batteries that @Rhinebeck01 recommended are out of stock... I found this at a local Batteries+ store: https://www.batteriesplus.com/productdetails/slipsaux14

Would this work on my Jeep?

Vehicle: 2018 JL, 3.6L Sport S

Thank you!

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[bthomp]

I started to get the ESS light to come on (and off intermittently) since Wednesday. I guess it's time to replace the aux battery. I had replaced the main battery back in December 2021 and I didn't take the advice of replacing both (i.e. aux and main batteries at the same time).

Some of the aux batteries that @Rhinebeck01 recommended are out of stock... I found this at a local Batteries+ store: https://www.batteriesplus.com/productdetails/slipsaux14

Would this work on my Jeep?

Vehicle: 2018 JL, 3.6L Sport S

Thank you!

I had a lot of problems with my 2019 ESS. Same as you, I replaced main first then the aux later. Was silly expensive for the aux as that battery is really hard to get to.

 

[CreepyCrepe]

Have you considered bypassing it?

 

[Geronimo]

I have the same exact issue on our 2018 JL. Am hoping that's all it is. Although thats enough, especially since we never use that function.

 

[aggiechris]

Bypass the ESS. One of the best things I did after it left me stuck on the trail.

 

[No IFS]

Get the ESS bypass module, over four years on my stock batteries. No issues

 

[Jebiruph]

I started to get the ESS light to come on (and off intermittently) since Wednesday. I guess it's time to replace the aux battery. I had replaced the main battery back in December 2021 and I didn't take the advice of replacing both (i.e. aux and main batteries at the same time).

Some of the aux batteries that @Rhinebeck01 recommended are out of stock... I found this at a local Batteries+ store: https://www.batteriesplus.com/productdetails/slipsaux14

Would this work on my Jeep?

Vehicle: 2018 JL, 3.6L Sport S

Thank you!

Typically when a bad aux battery triggers the error light, the light stays on. An intermittent light can be a sign of other issue like engine errors the disable ESS, but haven't met the threshold to turn on the CEL.

 

[Reinen]

Typically when a bad aux battery triggers the error light, the light stays on. An intermittent light can be a sign of other issue like engine errors the disable ESS, but haven't met the threshold to turn on the CEL.

Yeah but we're dealing with a relatively new Main and a very old Aux. So it's quite likely the Main is stronger but overburdened and the Aux is nothing but a vampire. That can easily cause brownouts of the electrical system in which case all bets ore off as to what the electronics should be telling you. Weird stuff can happen in that scenario.

 

[MesaAZGuy]

Curious if it can be replaced with a Lithium motorcycle battery if it is the same group size. I was thinking of swapping out my bike battery when it went low with a Noco Lithium but they were out of stock. Price as around $180

 

[Oncorhynchus]

Mine died after 15k miles and it was really dead, like in a good way. I got the alert that ESS is not functioning and I left it like that for months. Finally after happily living without ESS and not being OCD enough to be bothered by seeing that little alert light on the dash all the time, I figured I would get it replaced under warranty. Two months after dealer replaced the aux battery it died again, but this time in a bad way. It drains the main battery and I get no alert that ESS is not working. Had to get jump started today.

Decided to bypass the AUX battery as per Jebiruph:

https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

Will replace the aux myself once we get a nice warm weekend day.

 

[Valpo Jeep]

My 18 JLU has a build date of 5/18 and I just replaced both batteries. The AUX has a date of 10/18 on it so I am guessing the previous owner had issues and got it replaced. Could not find a date on my main battery. On the advise I read here on the forum I replaced both.

I got both of my batteries from O'Reiley's. $240 for the main and $105 for the AUX.

Most connections are 10mm sockets, I think I used an 8 mm somewhere and a 13 mm. 13 is optional. I wanted to disconnect the negative for the AUX at the main battery connection to get a voltage read on the AUX before removing. You will need a small reverse torx on the AUX battery terminals to swap the little battery post over to the new batteries.


To the OP, the battery you picked should work, its about the same price I paid. The battery you picked has a 6 month warranty whereas the 1 I got from O'Reiley has a 1 year warranty. For a bit more $$ ($130 - $150 depending on source) you can get the MOPAR battery and it has a 3 year warranty, just keep your receipt.

 

[HendersonJL]

Thanks, @Valpo Jeep.

So I bought the aux battery but havent replaced it yet, since the ESS light went away and hasnt popped up again, and ESS seems to be still functioning (at times when I forgot to turn if off).

When the temp gets a little warmer, I'll replace it.

Thanks all.

 

[Jebiruph]

Thanks, @Valpo Jeep.

So I bought the aux battery but havent replaced it yet, since the ESS light went away and hasnt popped up again, and ESS seems to be still functioning (at times when I forgot to turn if off).

When the temp gets a little warmer, I'll replace it.

Thanks all.

Your symptom is more in line with an engine issue than a bad aux battery. If the ESS light turns on again while you are driving, I would hook up a code scanner to see if there are any pending codes.

 

[jludave]

Your symptom is more in line with an engine issue than a bad aux battery.

It's not an engine issue. Intermittent issues with ESS are a symptom of a dying/worn aux battery (or main or both).

 

[HendersonJL]

Your symptom is more in line with an engine issue than a bad aux battery. If the ESS light turns on again while you are driving, I would hook up a code scanner to see if there are any pending codes.

I do hope that it's not engine issues and just a bad aux battery. Since last Wednesday, the ESS light hasn't come back on. I am contemplating whether to replace the aux battery or just by-pass it all togather.

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