Aux battery issue, need second opinion

[mjindy]

Having read several highly informative posts about AUX battery issues on this forum, I strongly suspect I too am victim of the same. I thought I will share my symptoms and seek second opinion.

Do you concur, the following behavior most likely indicates a failing Aux battery?

1. 2021 JLU Willy's, 2.0 with ESS, 32K miles, just out of warranty (sigh).
2. ESS has not worked for a while already.
3. AUX switches not available warning has been coming up lately, they do become available after about 30s of driving.
4. Per the dashboard screens, the primary batter maintains 12.4-12.6v in Acc mode and 14v+ in full ignition.
5. As such had no issues till this past weekend when I went offroad/camping.
6. At camp, the Jeep was not turned on (ignition) for about 48 hours. It was very cold. Doors were opened closed several times for normal camp style use. I even slept in it. When I tried starting the Jeep after those 48 hours, it wouldn't start. I had to jump it. It started fine after that.
7. But now, everytimeI start it, I have the Jeep warning me about ESS needing service, in addition to the AUX switches not being available.
8. On occassion, when I have the Jeep engine running, and the doors are opened to let someone out, I get key fob has left the Jeep warning. This has happened a couple.of times.
9. The main battery still looks fine from the dashboard screens.

Is my Aux battery failing? Could it have been responsible for draining my main battery?

Thanks.

My new car sticker states the warranty is good for 36000 miles. I’m having the same issues on the same year Jeep. I’m scheduled in the dealership this month. The 3 year warranty ends this month.

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[Willys41]

Just do what I and other have done
Disconnect the ground from the AUX battery and pull F42 fuse
Buy a Tazer or similar device to disable the ESS
A new AUX battery WILL fail again probably sooner than later
When the AUX battery fails it can cause all kinds of problems
When mine failed it fried my 8.4 radio

 

[Maverick909]

Batteries are failing. Might as well get the genesis dual battery kit and get your self a couple full battery’s instead of seal with aux batteries every couple years. Thus it is expensive to setup its well worth it

 

[loplop]

Having read several highly informative posts about AUX battery issues on this forum, I strongly suspect I too am victim of the same. I thought I will share my symptoms and seek second opinion.

Do you concur, the following behavior most likely indicates a failing Aux battery?

1. 2021 JLU Willy's, 2.0 with ESS, 32K miles, just out of warranty (sigh).
2. ESS has not worked for a while already.
3. AUX switches not available warning has been coming up lately, they do become available after about 30s of driving.
4. Per the dashboard screens, the primary batter maintains 12.4-12.6v in Acc mode and 14v+ in full ignition.
5. As such had no issues till this past weekend when I went offroad/camping.
6. At camp, the Jeep was not turned on (ignition) for about 48 hours. It was very cold. Doors were opened closed several times for normal camp style use. I even slept in it. When I tried starting the Jeep after those 48 hours, it wouldn't start. I had to jump it. It started fine after that.
7. But now, everytimeI start it, I have the Jeep warning me about ESS needing service, in addition to the AUX switches not being available.
8. On occassion, when I have the Jeep engine running, and the doors are opened to let someone out, I get key fob has left the Jeep warning. This has happened a couple.of times.
9. The main battery still looks fine from the dashboard screens.

Is my Aux battery failing? Could it have been responsible for draining my main battery?

Thanks.

This just happened to our 2020 which was 1 month out of warranty. Same initial experience you saw in 2-3. Both batteries flunked the test at the Jeep dealer, charging system and battery management system checked out OK. Tech stated that AUX failed and apparently the main will then be stressed and fail thereafter (in their experience). Was $900 to fix ($229 "diagnostic fee for diesel" and the rest was batteries and installation.

Dealer declined to ask Jeep for goodwill extension.

I contacted Jeep cares, and posited that the AUX certainly failed in warranty, without #3 showing until just after warranty. By the dealer's own admission this sealed the fate of the main battery, so my feeling is it would have been covered a month ago, it should be covered now.

Jeep Cares opened a case, it took about 5 biz days before I heard back. Rep said she'd contact the dealer and get back to me.

Dealer eventually called me a week or so after that, and said Jeep didn't approve the full amount, but rather would cover the AUX.

Jeep rep called me 2 hours after the dealer and said "I haven't spoken to the dealer yet, they won't return my calls and mail."

At this point I had enough of my dealer, so went and picked up the jeep as I didn't trust them. Paid $550-ish.

Jeep rep eventually DID get a hold of the dealer, dealer said I paid $350 for the service. Jeep rep said they'd cover that. I sent them the receipt for $550, they said it would probably get denied, would I accept the $350? I agreed, and they supposedly have mailed me a check for that (haven't seen it yet).

All shady as hell, and I'm done with all of them.

Hope that's helpful for you, keep advocating, try @JeepCares

 

[SoK66]

Having read several highly informative posts about AUX battery issues on this forum, I strongly suspect I too am victim of the same. I thought I will share my symptoms and seek second opinion.

Do you concur, the following behavior most likely indicates a failing Aux battery?

1. 2021 JLU Willy's, 2.0 with ESS, 32K miles, just out of warranty (sigh).
2. ESS has not worked for a while already.
3. AUX switches not available warning has been coming up lately, they do become available after about 30s of driving.
4. Per the dashboard screens, the primary batter maintains 12.4-12.6v in Acc mode and 14v+ in full ignition.
5. As such had no issues till this past weekend when I went offroad/camping.
6. At camp, the Jeep was not turned on (ignition) for about 48 hours. It was very cold. Doors were opened closed several times for normal camp style use. I even slept in it. When I tried starting the Jeep after those 48 hours, it wouldn't start. I had to jump it. It started fine after that.
7. But now, everytimeI start it, I have the Jeep warning me about ESS needing service, in addition to the AUX switches not being available.
8. On occassion, when I have the Jeep engine running, and the doors are opened to let someone out, I get key fob has left the Jeep warning. This has happened a couple.of times.
9. The main battery still looks fine from the dashboard screens.

Is my Aux battery failing? Could it have been responsible for draining my main battery?

Thanks.

Lead pipe cinch your AUX battery has either headed to the Promised Land or is packing for the trip. As suggested, replace both batteries. You can find better quality than what was supplied OEM. Some may disagree with my choices, but I'd go Optima yellow top (or high quality AGM deep cycle) in the main battery and the best OEM spec AGM for the AUX battery. Ain't cheap, but like everything Jeep "Bleed once, cry once."

I'm not sold yet that eliminating the AUX battery from the system is the best move. Due to the expense of the system and the manufacturer's number one objective of reducing costs, adding that second battery was the result of a lot of discussions, meetings, high level "gateway" approvals, etc. (I retired from an auto manufacturer). If they could have safely eliminated it and retained the ESS (stop/start), which is a CAFE must, they would have.

 

[Willys41]

Number one rule
Never never mix dissimilar battery's meaning size or type

 

[SoK66]

Watching these threads that involve Jeep Cares, as someone who ran customer service operations for a Jeep competitor, they'd be better off just telling their owners to go to hell than what they're doing. If they can't pony up another $200 bucks to help a customer they need to shut the phones off. Gezz....

 

[WorkingMan]

My batteries were replace just prior to the warranty running out. That was about 30k miles ago. Knowing I will have to deal with that again really sours me a little on my Jeep. Why did they have to bury that axillary battery?

 

[AndySpill]

Batteries are failing. Might as well get the genesis dual battery kit and get your self a couple full battery’s instead of seal with aux batteries every couple years. Thus it is expensive to setup its well worth it

I love the Genesis kit for dual battery JLs/JTs but think it a lot of $ to part with, not to mention installation time unless you plan on running overlanding appliances off your batteries while camping. In that case the additional power and power management capabilities, I think, are great.

 

[Maverick909]

I love the Genesis kit for dual battery JLs/JTs but think it a lot of $ to part with, not to mention installation time unless you plan on running overlanding appliances off your batteries while camping. In that case the additional power and power management capabilities, I think, are great.

It’s an easy install. Maybe two hours. 3.5 if you don’t have much hands on experience or even 3.5 if your enjoying a couple adult beverages of your choice.

I couldn’t fathom buying aux battery’s ever other year and 100+ bucks each and know that it isn’t going to last. Plus it’s a good upgrade if you run winch

 

[AndySpill]

It’s an easy install. Maybe two hours. 3.5 if you don’t have much hands on experience or even 3.5 if your enjoying a couple adult beverages of your choice.

I couldn’t fathom buying aux battery’s ever other year and 100+ bucks each and know that it isn’t going to last. Plus it’s a good upgrade if you run winch

We clearly have different opinions (which is perfectly okay!) on whether 3.5 hours is a fair amount of time to work on a Wrangler mod.

 

[Maverick909]

We clearly have different opinions (which is perfectly okay!) on whether 3.5 hours is a fair amount of time to work on a Wrangler mod.

It’s all about the enjoyment. I agree with you on the time everyone has different opinions which is great! . It’s all up to the owner. I’ve put all my suspension and axles in by my self in the driveways that took a few days

 

[Upnarms]

With all of the prior threads on this aux battery system (there may literally be dozens) has anyone actually had issues deleting it? So far, i have yet to hear anyone say they had a problem with a proper aux delete. Seems like all the friggin headaches they cause, it would be the go-to fix. I spent 500 bucks replacing them both the first time and i sure as heck will not buy 2 again. And im sure the genesis system is nice for the right application but i really want to avoid replacing 2 expensive batteries every 3 years, which is about all batteries last in AZ.

 

[Willys41]

When my 2 year old AUX battery failed it was the last straw
I did the aux delete and never have had any problems sense
Removed aux delete ground pull F42 fuse
I have done this on both my Wranglers with NO problems at all

 

[WhitneyWillys]

With all of the prior threads on this aux battery system (there may literally be dozens) has anyone actually had issues deleting it? So far, i have yet to hear anyone say they had a problem with a proper aux delete. Seems like all the friggin headaches they cause, it would be the go-to fix. I spent 500 bucks replacing them both the first time and i sure as heck will not buy 2 again. And im sure the genesis system is nice for the right application but i really want to avoid replacing 2 expensive batteries every 3 years, which is about all batteries last in AZ.

This is what I am wondering too! The Jeep community is often split with different opposite opinions on various matters. Here, when it comes to the pointlessness of the Aux battery, the community seems unified. Some of the pioneers of the disconnect method are now, apparently, driving this way for well over 50k miles. ??

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