Jumperless Aux Battery Bypass

[Cuyose]

Its crazy there are about 40 ways to do this and I can't figure out which one is the right one. Some say remove fuse, some say jump N2 and N3, some say run positive from aux to positive of main and tape off one of the negatives at main.

Sponsored

 

[Heimkehr]

Its crazy there are about 40 ways to do this and I can't figure out which one is the right one. Some say remove fuse, some say jump N2 and N3, some say run positive from aux to positive of main and tape off one of the negatives at main.

There are multiple methods, based on what the owner decides to do.

E.g., removing the ESS battery from the vehicle requires certain steps that aren't necessary when it's left in situ. If the ESS battery is removed, the owner then has to decide if he's going to leave the associated cables in the vehicle (which then need to be managed properly), or completely removed...which has its own process.

You just need to know what you want to do, and then follow the correct steps. The easiest and most popular approach is to disconnect and tape off the ESS Negative cable, and remove Fuse F42. Done.

 

[Cuyose]

There are multiple methods, based on what the owner decides to do.

E.g., removing the ESS battery from the vehicle requires certain steps that aren't necessary when it's left in situ. If the ESS battery is removed, the owner then has to decide if he's going to leave the associated cables in the vehicle (which then need to be managed properly), or completely removed...which has its own process.

You just need to know what you want to do, and choose the correct solution to do so. The easiest and most popular approach is to remove and tape off the ESS Negative cable and remove Fuse F42. Done.

I have everything hooked back up and on charger, as regardelss of what I do, my "press brake and push button" lights stay on, and infotainment cycles of and on repeatedly all night. Taping negative off and pulling f42 didnt change anything and when charger is hooked up it is charging and showing 12.6 volts and climbing.

 

[Heimkehr]

I have everything hooked back up and on charger, as regardelss of what I do, my "press brake and push button" lights stay on, and infotainment cycles of and on repeatedly all night. Taping negative off and pulling f42 didnt change anything and when charger is hooked up it is charging and showing 12.6 volts and climbing.

Just an FYI: The charger's Negative connection should be secured on top of the stud that connects to the Intelligent Battery Sensor. It shouldn't be connected directly to the Negative stud on the battery itself. The IBS has to recognize the state of battery health at all times, to include charging events when the vehicle isn't running.

Also, if your batter(ies) are at least four years old, consider replacing one or both as a prophylactic measure. Use AGM.

 

[Cuyose]

Just an FYI: The charger's Negative connection should be secured on top of the stud that connects to the Intelligent Battery Sensor. It shouldn't be connected directly to the Negative stud on the battery itself. The IBS has to recognize the state of battery health at all times, to include charging events when the vehicle isn't running.

Also, if your batter(ies) are at least four years old, consider replacing one or both as a prophylactic measure. Use AGM.

Unfortunately, thats exactly how the charger is hooked up, both batteries are less than a year old, and still dash keep cycling.

 

[THAW]

Unfortunately, thats exactly how the charger is hooked up, both batteries are less than a year old, and still dash keep cycling.

https://www.jlwranglerforums.com/fo...-off-when-vehicle-is-parked-and-locked.61693/

 

[Cuyose]

https://www.jlwranglerforums.com/fo...-off-when-vehicle-is-parked-and-locked.61693/

Thanks!

I read that before, and it went way over my head with testing pins and stuff, didn't even know where to find the connector he was talking about. Then I looked up C6 connectors, and I'll be damned, just the door electric connectors I take off all the time. Well, went out and dash was on, hear relays cycling infotainment cycling, etc. Disconnected door electrics and holy crap if the front passenger door didn't stop the symptoms. Closed and locked Jeep, 30 second all shut down and no longer cycling!

 

[PrimeTime4370]

Thanks!

I read that before, and it went way over my head with testing pins and stuff, didn't even know where to find the connector he was talking about. Then I looked up C6 connectors, and I'll be damned, just the door electric connectors I take off all the time. Well, went out and dash was on, hear relays cycling infotainment cycling, etc. Disconnected door electrics and holy crap if the front passenger door didn't stop the symptoms. Closed and locked Jeep, 30 second all shut down and no longer cycling!

I would check for bent pins or damaged wires.

 

[Cuyose]

I would check for bent pins or damaged wires.

Yeah, I take those off all the time, and one time I had to reset a pin in that same connector when the door ajar light wouldn't go off. I hadn't messed with them though since summer.

 

[aeonixx1001]

Hello, looking for advice.

I have a 2021 Wrangler, 2.0.
Since purchasing a year ago, start / stop never worked unless I did a 4+ hour drive or left it on the maintainer. NO error messages, always just " not ready "

First winter now, no start, boost gets her going and than needed another boost a couple days later. Bypassed AUX, pulled 42. Issue persist. Replaced main battery, things are good for a few days now.


My question, I'm wondering if this whole time it was the main being the original issue. When I connect my Noco genius to the negative AUX cable, after a few hours the LED states bad battery. IS this because I have 42 removed? Looking at diagrams that AUX negative might not go directly to the Aux battery.

Also, my 2021 AUX battery cable was the smaller cable without the post. Looking at other forum posts, it says the 2021+ should be the larger L looking post. IS this correct?

If you are connecting the battery tender directly to the battery the power control relay (F42) would not be in the circuit. Direct battery connection, correct? That Aux battery goes bad it is a main battery killer. I have had mine removed for quite some time now with no issues.

 

[Gangplank]

Is it Groundhog Day?

 

[Dustonfoster]

If you are connecting the battery tender directly to the battery the power control relay (F42) would not be in the circuit. Direct battery connection, correct? That Aux battery goes bad it is a main battery killer. I have had mine removed for quite some time now with no issues.

hmm, not direct connect. I have the positive on the main battery lug where the wires all come together and the negative on the Aux cable. However I’m just not certain that negative aux cable goes directly to the aux battery?

too cold outside for me to dig out the aux battery.

 

[THAW]

hmm, not direct connect. I have the positive on the main battery lug where the wires all come together and the negative on the Aux cable. However I’m just not certain that negative aux cable goes directly to the aux battery?

The AUX (ESS) battery ground cable goes directly to the AUX (ESS) battery (from the CR[an]K battery negative terminal connector, where you presumably disconnected it).

Fuse F42 is for the PCR on the AUX (ESS) battery positive cable; pulling the fuse ensures the positive connection is never broken, so pulling the fuse had no impact on your charging setup.

 

[mojitorob]

Anybody still get an Autostart issue warning or have issues with remote start after doing the bypass and pulling fuse 42? I did the bypass about 2-3 months ago after getting the autostart not available light and message a few times. Also noticed the volts were 14.8, so seemed to be charging high.

Recently I’ve been having issues with remote start failing, and have seen a similar auto start message once or twice. I figure it’s probably my main battery at this point. It probably went through hell supporting the aux battery and maybe on its way out. Before buying a main I figured I’d ask.

 

[zouch]

not i.
but i replaced the Main Batt at the same time i bypassed the Aux Batt and pulled Fuse 42.

Remote Start works fine, and no error messages. ESS works as designed (if i let it), but i have it disabled almost all the time via Tazer.

Anybody still get an Autostart issue warning or have issues with remote start after doing the bypass and pulling fuse 42? I did the bypass about 2-3 months ago after getting the autostart not available light and message a few times. Also noticed the volts were 14.8, so seemed to be charging high.

Recently I’ve been having issues with remote start failing, and have seen a similar auto start message once or twice. I figure it’s probably my main battery at this point. It probably went through hell supporting the aux battery and maybe on its way out. Before buying a main I figured I’d ask.

Sponsored