Isolating AUX battery. Which negative cable?

[tonywin]

I’m trying to isolate my AUX battery and pull fuse 42 until I can decide what I want to do with my battery setup.

Can anyone help me confirm which cable it is from the negative post? I heard 2 different answers from my research. Mine is a 2020.

Please excuse the dust from all the wheeling trips.

Sponsored

 

[Andy29847]

On my 2020, it's the one with the big nut. It would be on the bottom of your photo.

 

[Lunentucker]

2020 should be the smaller ground cable that routes down towards the auxiliary battery. You can rule out two cables by following them to the ground block on the fender. Then it's the smaller of what's left.

 

[Lunentucker]

A simple meter that tests continuity should be helpful.

 

[mrmo]

I want to completely eliminate my Aux/ESS batt and remove the wiring. I understand the removal of the IBS, what about the PCR (Pwr Ctrl Relay)? If I unwire it does anything else get affected? Pull fuse N3 and leave the relay in place Im assuming.

 

[Andy29847]

I want to completely eliminate my Aux/ESS batt and remove the wiring. I understand the removal of the IBS, what about the PCR (Pwr Ctrl Relay)? If I unwire it does anything else get affected? Pull fuse N3 and leave the relay in place Im assuming.

I would not remove the IBS. I'm not sure what would be the effect on the brains of your Jeep.

Your vehicle should be fine with just one battery. Disconnect the 2 cables for the aux battery, pull fuse F42, and remove the power control relay and associate wiring. I understand you save 11 pounds. Your stop/start will still be functional. I normally hit the stop/start button when the system operates the first time. When it's time to replace your main battery, I'd recommend buying one of the premium Group 94/H7 batteries. These batteries will fit in the tray and can be found rated up to 900 Cold Cranking Amps.

Pages and pages of discussion can be found at the thread listed below. I had some reservations about disconnecting the aux battery when I first started considering it. I got past the reservations a few weeks ago and all is well.

Jumperless aux battery/PCR bypass | Jeep Gladiator Forum - JeepGladiatorForum.com

 

[tonywin]

I just pulled the aux negative cable from the main battery post and removed fuse 42. This should not allow the aux to drain the main battery now correct? Do I need to remove the ground as well?

 

[SaplingT]

Anyone have input on which negative to remove on 2022 diesel? There is a larger wire and smaller wire. Larger wire is on the offset of the ibs and the small wire is directly over the ibs.

Both go into the harness and aren't easily chased to see which goes to the AUX both are grounded at the chassis so both show voltage...

I would like to simply disconnect the AUX ground and pull fuse 42.

It seams strange that the smaller wire would be big enough to support starts loads etc...

Looking at it closer the smaller ground is actually the splitter plate that allows both grounds to attach at the terminal... It can't be disconnected without redoing that plate.

Maybe I just go ahead and pull the battery out and attach both ends to the terminals to be safe.

 

[Mr._Bill]

Anyone have input on which negative to remove on 2022 diesel? There is a larger wire and smaller wire. Larger wire is on the offset of the ibs and the small wire is directly over the ibs.

Both go into the harness and aren't easily chased to see which goes to the AUX both are grounded at the chassis so both show voltage...

I would like to simply disconnect the AUX ground and pull fuse 42.

It seams strange that the smaller wire would be big enough to support starts loads etc...

Looking at it closer the smaller ground is actually the splitter plate that allows both grounds to attach at the terminal... It can't be disconnected without redoing that plate.

Maybe I just go ahead and pull the battery out and attach both ends to the terminals to be safe.

Disconnect both wires from the negative post. Use a meter to determine which one is the body ground and which one is the negative post of the Aux battery.

 

[ShadowsPapa]

The one marked 2020 is the aux battery ground cable for model year 2020

The one marked 2021+ is the aux battery ground cable for model year 2021 and later

The arrow points to the IBS - DO NOT REMOVE THAT! It's NOT part of the auto/stop start system.
Again, DO NOT REMOVE the IBS, it has nothing to do with anything ESS related, nothing.

 

[ShadowsPapa]

I just pulled the aux negative cable from the main battery post and removed fuse 42. This should not allow the aux to drain the main battery now correct? Do I need to remove the ground as well?

But what happens when the main battery goes bad? Just as big a chance of that as there is the aux battery going bad.
It's not a given that the aux battery will drain the main - that's internet lore.
it's just as likely the main goes bad and drains the aux battery.
So you still have a chance of being stranded with a bad battery out in the middle of nowhere, just not due to the aux battery.

 

[SaplingT]

The one marked 2020 is the aux battery ground cable for model year 2020

The one marked 2021+ is the aux battery ground cable for model year 2021 and later

The arrow points to the IBS - DO NOT REMOVE THAT! It's NOT part of the auto/stop start system.
Again, DO NOT REMOVE the IBS, it has nothing to do with anything ESS related, nothing.

This is exactly what I was looking for. Thank you!! I definitely left the IBS. I ordered a terminal block to attach so I can attach the rest of my accessories back to a larger 12mm lug.

Got it done and pulled 42 and it works perfectly!

Thanks again!

 

[Orange01z28]

I removed fuse 42 and the aux negative cable according to @ShadowsPapa ‘s diagram. ESS error message is gone and Jeep is good to go! Thank you!

however, do the rest of you who’ve done this experience what sounds like a starter tick and a slight pause upon startup?

 

[jay21mojave]

I removed fuse 42 and the aux negative cable according to @ShadowsPapa ‘s diagram. ESS error message is gone and Jeep is good to go! Thank you!

however, do the rest of you who’ve done this experience what sounds like a starter tick and a slight pause upon startup?

All, you won't want to hear this .. I did exactly this and guess what still operates - intermittently ? Start STOP functioned 2 times yesterday; checked with my other driver and he reported same only occasionally and without any unusual operations. Put fuse 42 back in left cable disconnected and reverted to using the BUTTON to Turn Off. Any and All thoughts appreciated.

 

[Orange01z28]

ESS can still function on one battery from what I’ve read.

it seems like the pause is only on cold startup

Sponsored