This Confuses Me

[AndySpill]

I run one battery and hit the ESS off button the first time I think about it. I have considered buying one of the stop/start off devices but I can't bring myself to write the check.

I've tried driving with the aux battery disconnected and the F42 fuse in. It works like you say. I don't mind the "Avenger" light just above the gas gauge. What I don't like is the message screen displaying "service stop/start system" while I drive. I believe that this message will always appear on start. A driver can scroll away from the message which is almost the same as turning off the stop/start using the button every time you drive. Unknown for me is if the constant "service stop/start system" will prevent a driver from seeing another more important message. Also, in the event that a Jeep driver ever has to take their vehicle in for service, chances are the service tech is going to react to the "service stop/start system" message.

FWIW, I believe that my Jeep, the one where I deleted the aux battery and removed the F42 fuse, operates exactly as designed except for the cold crank test. I think the cold crank test is still made, it's just that there is no battery separation step. The cold crank test sees the main battery. In the event the main battery fails the cold crank test, the Jeep probably would not start anyway. Boosting the Jeep (with one battery) should work just like the other cars and trucks I have had over the decades.

Here's what I *think* happens. The cold crank test happens and the first time you try to crank after disconnecting the Aux battery, but keeping Fuse 42 intact, the rig doesn't crank. For that point on the test of the Aux battery still happens (I think) but in failure to acquire power solely from the Aux battery the JL's programming chooses to then continue on to deenergize the relay that separates the batteries, controlled by Fuse 42, and attempts the crank off the main battery.

I am not certain. I am certain that this doesn't happen in early model 2018s that haven't been flashed. A dead Aux battery strands you.

And I believe this is the case because once you reintroduce the Aux battery into the power plant, on the next cold crank (I tried it) the ESS off light in the EVIC shuts off.

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[AndySpill]

Andy

I don't think you are missing anything, you seem well informed.

IMO,

Most know pulling fuse 42 isn't absolutely necessary in order to turn off the ESS... but they pull it to do away with dash lights and other ESS system warnings. The only true usefulness of pulling fuse 42 I can see, is if the lights/warnings bother you.

Me personally, I don't want to see the warning lights and I don't want to have to push my ignition button more than once to crank the vehicle.

In my case, I just don't care for the ESS system in general. I still have both oem batteries installed and I also have an ESS eliminator installed. I installed it because I don't want any extra dash lights, I want my ESS system to remain off as designed and I want my ESS to remember to remain off without me having to push the ESS on/off button at every start.

I am not ready to separate or delete the aux battery or make any other mods concerning battery or ESS at the moment, so this works for me.

The biggest reason and one I haven't seen mentioned yet, in favor of the ESS eliminator tech, is I can still turn on/off my ESS whenever I want and I can have that setting remembered until I decide to change it... for me, it makes my purchase well worth it.

I completely respect the path you took, content to know it was NOT ignorance based on your part, but born of desire to not see warnings on the dash, and plain old fashion convenience--which you have every right to spend $ on to achieve: we all do in different ways.

It bothers me though if people are buying this ESS off tech, not disturbed by such messages informing that the the JL has turned ESS off for them, born of ignorance that the need this tech or must, following best practices, turn ESS off manually each time they cold crank.

Again--all said with the caveat that there isn't more to keeping the ESS off light from appearing in the dash than personal taste that I am missing. ?

 

[Al G]

Why is it so hard for you to accept that some people just don't want to see a useless warning on the dash? The more you say the more it sounds like you just want to act like you're smarter than everyone else.

 

[AndySpill]

Why is it so hard for you to accept that some people just don't want to see a useless warning on the dash? The more you say the more it sounds like you just want to act like you're smarter than everyone else.

I don't think that it's a useless warning. It's telling you that your vehicle has shut ESS off for you so that you don't have to spend at least $50 on a start stop eliminator, or more for a JL Tazer to turn ESS for you automatically. I get and respect that some people are willing to shell out $ so that they see idiot lights. Certainly a "check engine soon" one would upset anyone. But a light telling you that something you want to have happen (ESS being turned off) is so offensive that all people who go the 1 battery route buy stuff to keep that light off, but the one on the ESS off switch on?

I don't believe that. Rather I believe that yes, for some it is the annoyance of the light, or the desire to own a JL Tazer for other reasons anyway, and for others it's ignorance, or I miss (because I'm not "so smart") as I've repeatedly said, good reasons for keeping this ESS off light from making its way to the EVIC .

The humility of admitting possible ignorance isn't, at least I think, the stuff of know it alls, nor is politely correct people who've made flat out wrong points here.

You can disagree if you want.

 

[SargeDiesel]

I don't think that it's a useless warning. It's telling you that your vehicle has shut ESS off for you so that you don't have to spend at least $50 on a start stop eliminator, or more for a JL Tazer to turn ESS for you automatically. I get and respect that some people are willing to shell out $ so that they see idiot lights. Certainly a "check engine soon" one would upset anyone. But a light telling you that something you want to have happen (ESS being turned off) is so offensive that all people who go the 1 battery route buy stuff to keep that light off, but the one on the ESS off switch on?

I don't believe that. Rather I believe that yes, for some it is the annoyance of the light, or the desire to own a JL Tazer for other reasons anyway, and for others it's ignorance, or I miss (because I'm not "so smart") as I've repeatedly said, good reasons for keeping this ESS off light from making its way to the EVIC .

The humility of admitting possible ignorance isn't, at least I think, the stuff of know it alls, nor is politely correct people who've made flat out wrong points here.

You can disagree if you want.

Scratching my head a little, I think the "MAIN" reason I purchased an ESS eliminator was primarily for the memory function. I like knowing I can still push the oem ESS button anytime I want and have the system function as designed... but my preference is to typically have it turned off, it's nice to "set and forget"... and for it to stay off until I desire it to function. I think not seeing the malfunction light or warning messages is just a bonus... but I will say, if you do/want to use an ESS eliminator, do your homework, they are not all created equal...

Maybe an updated topic for the thread could/should be:

1. Why did you pull fuse 42 ?
or
2. Why did you purchase an ESS eliminator ?

Maybe add a poll to see the % breakdown of the main reasons ?

 

[Jebiruph]

The ESS warning light is an early warning system for other issues like engine misfires. If this light gets triggered while you are driving, it means that there is an issue somewhere and ESS has been disabled. This is what happened to me when I was having misfires, the ESS error light would turn on before the misfire count reached the threshold to throw an error code and light the CEL.

 

[AndySpill]

The ESS warning light is an early warning system for other issues like engine misfires. If this light gets triggered while you are driving, it means that there is an issue somewhere and ESS has been disabled. This is what happened to me when I was having misfires, the ESS error light would turn on before the misfire count reached the threshold to throw an error code and light the CEL.

Thanks Jerry. This is the first post I've seen on the thread with reasons to not disconnect Fuse 42 beyond visual annoyance.

For those just tuning in, Jerry is the Godfather of all of this. He originally published here the technique to Fuse Jumper N1 and N2 on the PDC to bypass the effects of the relay whose function is made possible by an intact Fuse 42, and then subsequently determined that merely pulling this fuse would make the fused jumper not wrong, but moot.

 

[AndySpill]

Scratching my head a little, I think the "MAIN" reason I purchased an ESS eliminator was primarily for the memory function. I like knowing I can still push the oem ESS button anytime I want and have the system function as designed... but my preference is to typically have it turned off, it's nice to "set and forget"... and for it to stay off until I desire it to function. I think not seeing the malfunction light or warning messages is just a bonus... but I will say, if you do/want to use an ESS eliminator, do your homework, they are not all created equal...

Maybe an updated topic for the thread could/should be:

1. Why did you pull fuse 42 ?
or
2. Why did you purchase an ESS eliminator ?

Maybe add a poll to see the % breakdown of the main reasons ?

With deference to Jerry's legitimate reason post immediately above https://www.jlwranglerforums.com/forum/threads/this-confuses-me.123060/page-3#post-2568158 to justify taking the steps that you did, that said--and this perhaps was the essence of my point--you buying tech to set it and forget it would have been handled for you by the vehicle by keeping Fuse 42 intact and letting the vehicle do the setting (if not forgetting) for you; the latter reminded by the ESS off EVIC light in the dash.

 

[THAW]

I'd more want a Genesis Offroad like Setup that merely alternates which equally sized AGM battery under the hood plays the role of main, and which of Aux: no fancy offroad power mgmt needed for me.

Not really related to your original question, but the batteries size being equal doesn't do anything to fix the problem of disconnecting the batteries, depleting one battery, reconnecting (instantly equalizing) the batteries, and then "charging" them with a smart alternator. That process is hard on batteries irrespective of the size differential.

 

[THAW]

I look at fuse 42 this way: once the aux battery is disconnected, why leave the relay that disconnects the main battery from most of the vehicle electronics enabled?

Your answer is obviously to disable ESS, but to me there are much cleaner and more versatile - albeit more expensive - ways (mine being the Tazer).

 

[AndySpill]

Not really related to your original question, but the batteries size being equal doesn't do anything to fix the problem of disconnecting the batteries, depleting one battery, reconnecting (instantly equalizing) the batteries, and then "charging" them with a smart alternator. That process is hard on batteries irrespective of the size differential.

Fair. Harder when using dissimilar sized batteries as does Stellantis. Agreed?

Maybe the ability for the alternator to charge the batteries indepedently after an ESS event, to bring them closer to voltage parity before (if) connecting them might avoid the shock you describe of putting them in parallel with such potential post ESS event voltage disparity.

Then again, given the lack of quality of batteries these days I've resolved to a need to replace both every 3 years and trickle charge them at rest.

 

[AndySpill]

I look at fuse 42 this way: once the aux battery is disconnected, why leave the relay that disconnects the main battery from most of the vehicle electronics enabled?

Your answer is obviously to disable ESS,

Right, and in a way, prior to Jerry's @Jebiruph point, in a way that doesn't involve the purchase of tech to do it for you if you can tolerate EVIC lights.

but to me there are much cleaner and more versatile ways (mine being the Tazer).

I get it. This whole thread for me was academic. I'm like Jay above @jeepoch . I run dual batteries, trickle charge, live in fool's paradise that I'm saving money on gas at stop lights while I'm spending on the energy and equipment to trickle charge. And I even own a JL Tazer. Its ability to be a "rear view mirror " for me when gear's loaded that blocks the rear view mirror is alone worth it for me, even if I never use it to turn ESS off.

But my point is people pay a price for that cleaner way in tech, that I guessed that at least some might have thought twice about who couldn't care less about EVIC lights, but purchased in ignorance.

And why I can completely respect your direction was it was aesthetic, not ignorance born.

Peace.

 

[THAW]

Fair. Harder when using dissimilar sized batteries as does Stellantis. Agreed?

Though the dissimilar size certainly doesn't offer any advantage, as far as I know It's the small capacity of the second battery that causes it to go bad first (then wreak havoc on the larger battery).

 

[AndySpill]

Though the dissimilar size certainly doesn't offer any advantage as far as I know It's the small capacity of the second battery that causes it to go bad first (then wreak havoc on the larger battery).

Well, there's one "advantage" a cheaper vehicle purchase price, not that Wranglers are inexpensive.

How nice it must be for Wrangler engineers to say, "who cares if we make it substandard, we have so little competition and the aftermarket will just provide solutions need be."

 

[THAW]

But my point is people pay a price for that cleaner way in tech, that I guessed that at least some might have thought twice about who couldn't care less about EVIC lights, but purchased in ignorance.

I agree, I'd guess a lot of people prefer the convenience of purchasing a packaged solution to taking time to understand how the aux battery and ESS systems actually work.

To be honest, it is a bit intimidating and confusing. to wade through all the forum posts on the subject. It took me quite some time before I fully understood the systems (including model variations), and I only spent the time because I enjoyed learning about them.

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