My AUX Battery Bypass and ESS Disable

Lunentucker

Hooked
Not trying to outdo our host here.
I am not an influencer and don't even want to be.
Just a simple condensed 1 minute video on the simple process.


NOTES:
If you remove the wrong cable you'll know it pretty quickly, because the Jeep will not have power.
Your subscriptions, display themes, etc. may take a while to come back. Mine were all back the next day.
I would advocate this over full removal at least until your warranty has expired.
I saw another video where the owner removed the fuse first, and then removed the cable. His ESS Off button now shows ESS as being OFF (light on) when the Jeep is started. My light is off, but it will come on if I press the button. Of course, either way, ESS will not implement with the fuse removed. I just found that interesting.

WHY DO THIS?:
Physically separating the two batteries prevents the very common issue that many owners have experienced. That issue is that the AUX battery will begin dying, and it will start cannibalizing the primary battery trying to recharge itself. This often occurs with little to no warning, and it can leave you high and dry, unable to start the vehicle, and in some cases even unable to jump start it, without disconnecting the two batteries.

FAQ:
Does this put my electronics in jeopardy, because the AUX battery is there to keep them stable during ESS cycles?
No. You actually just answered the question for me. Since this process disables ESS, there's no reason to have a second battery in place to keep the electronics at full voltage while the engine is off. In fact, the malfunctioning AUX battery may even have the reverse effect. many owners have seen the "light show" occur when the AUX is failing. Displays and electronics go haywire and you get all kinds of error messages. It can even render the vehicle inoperable until you break the connection and properly recharge the primary battery.

Will this void my warranty?
I don't know. Certainly some dealerships look for a reason to deny a claim, and if they find this has been done, then they'll probably try to use it on any electronics claims. That's why I advocate doing it this way, which is easily reversible when you might need to take the Jeep in for service or claims. At least until the warranty has expired.

But if my warranty is bumper to bumper, including batteries, why would I want to do this?
Well, it's risk management issue for me. I don't want the light show and I don't want to get stranded on top of a mountain somewhere. My dealer isn't sending a rollback up there to save me. You make the choice that you think best suits you.
 
Fascinating. My wife wants me to get a new AUX battery because we did see the "light show" you mention, but it was a main battery failure. Luckily it happened in the garage, right as we were to embark on a 2000 mile trip.

It seems that most Chrysler type vehicles have these AUX batteries.
 
I've been tossing around the idea of disconnecting the Aux battery on my JL.

Currently my ESS set to off with the Tazer setting but only if the last setting was disabled.

This seems like it would keep it off even if the Tazer is not connected.

Without any charge going to the Aux battery, it would eventually die; I'm guess it would be ok to disconnect the aux battery completely and remove it.
 
I've been tossing around the idea of disconnecting the Aux battery on my JL.

Currently my ESS set to off with the Tazer setting but only if the last setting was disabled.

This seems like it would keep it off even if the Tazer is not connected.

Without any charge going to the Aux battery, it would eventually die; I'm guess it would be ok to disconnect the aux battery completely and remove it.

Yes. I'll do that after the warranty is up.
 
Fascinating. My wife wants me to get a new AUX battery because we did see the "light show" you mention, but it was a main battery failure. Luckily it happened in the garage, right as we were to embark on a 2000 mile trip.

It seems that most Chrysler type vehicles have these AUX batteries.

The main will feed the dead AUX and mask the issue. if your AUX battery is bad it will draw the life out of the main eventually. Even the new one.
It's best to isolate them and ten test separately. Together you can't tell which is the problem.
 
The main will feed the dead AUX and mask the issue. if your AUX battery is bad it will draw the life out of the main eventually. Even the new one.
It's best to isolate them and ten test separately. Together you can't tell which is the problem.
If my AUX battery was/is bad, then it is well disguised since it has been over 3 years since the "event". Most driving has been highway driving and I have taken care to attach a good battery tender when it is idle for some weeks. The dealership claimed that they did test the AUX battery (twice already) and it was fine.

Regardless, a battery which is not readily available (and is also difficult to install) makes me more nervous. Outside of a major urban area, the closest replacement battery could be 200 miles away.

At least Jeep came out with a new model of the AUX battery to try to address reliability concerns.
 
Nice video and write-up. Thanks.

Does the disconnect of the AUX battery, along with the bypass of ESS by removing F42 fuse make jumping the remaining battery like any single battery system? I am assuming it would, but ...
 
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Nice video and write-up. Thanks.

Does the disconnect of the AUX battery, along with the bypass of ESS by removing F42 fuse make jumping the remaining battery like any single battery system? I am assuming it would, but ...

Yes. It should be no different.
 
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