Jumperless Aux Battery Bypass

[bigfoot21075]

Something odd. I got to take the Jeep out for a ride today, I have the Tazer, but after I changed the battery the tazer no longer kills the auto stop start feature and I have to hit the button. I was trying to figure out why. I would have thought if it unmarried, my speedo would go back to being off.

Also, for some reason, even though I replaced the main battery. all of my radio presets were still there. Does this mean I did something wrong? The jeep starts and runs perfectly, it charges at14+ volts the entire time.

**EDIT** in my case it is pure paranoia! I double checked, I removed the correct fuse 42, and if I had taken off the wrong ground wire, the Jeep wouldn't start! I took it for a quick spin and the Tazer is working as it should now, the volt gause shows 13.8-.9 now. Weird, just like ROADKILL, it fixed itself.

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[Sdchrisc]

Mine charges at 14.5v constantly too.. wonder if i did something wrong.. my aux is out and aux negative cable is completly disconnected from both ends and aux positive it all taped up on aux battery connector side.. brand new h7 battery too.. is it normal to charge at 14+ constantly when the vehicle is on?

 

[Sdchrisc]

So a month ago I did this bypass, removing the fuse and disconnecting the negative cable for the auxiliary battery and yesterday I started getting the ESS service warning indicator. Any idea why this is happening? Main batteries fully charged no taser no other modification. I have an 2018 JLU sport.

Same issue.. I think our IBS sensors faulty and needs to be replaced.. light randomly goes on so sometimes its fine.. runs fine for now.

 

[hobbsserv]

Mine charges at 14.5v constantly too.. wonder if i did something wrong.. my aux is out and aux negative cable is completly disconnected from both ends and aux positive it all taped up on aux battery connector side.. brand new h7 battery too.. is it normal to charge at 14+ constantly when the vehicle is on?

I have the same question. ?

 

[Leisure Freak]

I have the F42/Aux Bat cable bypass and have the same constant 14.4-14.7 smart charge occur in cold weather months. In warm weather months it is 13.X-14.3. If I do any road tripping in cold weather months it will eventually hit the 13v range. I only drive about 10 to 15 miles a day with some days having no driving so as many say on the forum, it isn't driven enough to really charge it up. However, I have tested this voltage reading by putting the trickle charger on it to full charge and it still reads the same 14.x during the drive in cold months. Stangely, the more restarts I have running errands, the lower the voltage charge will read in the same 10-15 mile route. I mentioned the constant 14+v during dealer servicing early in ownership and they said it was normal. That was 4+ years ago and no trouble with the lower output base Sport alternator. I have just decided to go with it instead of worry about it.

 

[PeatedWhisky]

Charging voltage compensates for the effects of temperature. The cooler the temp, the higher the voltage. Here's a chart showing some typical values: https://tengtoolsusa.com/blogs/news/12-volt-battery-charging-guidelines-for-cold-hot-weather

Float is basically a full battery being maintained. Absorption would be what it is pushing into the battery to charge it and is a bit higher.

Note, that that chart is probably for a specific type of Flooded Lead Acid battery, not the AGM battery for a Jeep. However, the principals are the same, but the precise voltage values may be slightly different but should be in the same ballpark. In short, I don't think there's an issue with 14.x volts.

 

[MonsterTorch]

Just wanted to thank you for this thread and information included. My JLR sat for a few days, went to start it yesterday, all the electronics came on, and the starter went click click click… I remembered reading this thread previously, and checked it again last night…

Today I did the following:
- I pulled F42
- I disconnected the thinner of the three negative cables (I’ve got a winch installed, hence three)
- jeep started on first attempt
- properly wrapped and secured the ESS negative so it won’t ground or flop
- used a piece of blue tape, tapped the F42 fuse on the inside cover of the fused box, and wrote F42 on either side
- took a 20 min drive, no issues

I’ll watch and see what state the main battery is in. I’m hoping it isn’t affected too much, but I’m prepared to replace it if needed. Looks like the original owner replaced it with a Napa branded battery (H794R, factory tow kit), so I don’t know the exact age (couldn’t find the date tag).

I should mention, I’ve had the ESS override installed since the first week I got my JL. I hate the feature, makes me think there’s something wrong and I get flashbacks of my first car stalling at a red light back in the day. I get an override for all our vehicles lol

again, thank you all, hopefully this solves my issue. Have a great day!

 

[steelponycowboy]

Just wanted to thank you for this thread and information included. My JLR sat for a few days, went to start it yesterday, all the electronics came on, and the starter went click click click… I remembered reading this thread previously, and checked it again last night…

Today I did the following:
- I pulled F42
- I disconnected the thinner of the three negative cables (I’ve got a winch installed, hence three)
- jeep started on first attempt
- properly wrapped and secured the ESS negative so it won’t ground or flop
- used a piece of blue tape, tapped the F42 fuse on the inside cover of the fused box, and wrote F42 on either side
- took a 20 min drive, no issues

I’ll watch and see what state the main battery is in. I’m hoping it isn’t affected too much, but I’m prepared to replace it if needed. Looks like the original owner replaced it with a Napa branded battery (H794R, factory tow kit), so I don’t know the exact age (couldn’t find the date tag).

I should mention, I’ve had the ESS override installed since the first week I got my JL. I hate the feature, makes me think there’s something wrong and I get flashbacks of my first car stalling at a red light back in the day. I get an override for all our vehicles lol

again, thank you all, hopefully this solves my issue. Have a great day!

Just remember that if you have any electrical issues and the dealer sees what you did that they can void part of your warranty and deny any claims. Happened to me twice now and attorney says not worth trying to fight it because Jeep will win due to the owners modifications. Magnussen act will NOT protect you if and when you make any modifications to your Jeep. You have to prove them wrong, they will bring expert witnesses and beat you every time.

 

[Billyg73]

Alright, which ground is the aux connect. I took off the one with the bigger bolt on top and jeep was DOA. It was so hot this past weekend I didn't get into it deeper.

 

[bigfoot21075]

Alright, which ground is the aux connect. I took off the one with the bigger bolt on top and jeep was DOA. It was so hot this past weekend I didn't get into it deeper.

Have a look at this, I had the same issue but found this post - there was a cable location change.

https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/

 

[cpawlFL]

Thanks for the info in this thread. Just completed the bypass this morning because the light came on this week. Second time since owning it, the first was handled under warranty. First couple starts and drives, everything seems good so far. The ESS is such a useless system. Just need to by an Auto Start Stop Eliminator of some kind now.

 

[SonofaSeabee]

Thanks for the info in this thread. Just completed the bypass this morning because the light came on this week. Second time since owning it, the first was handled under warranty. First couple starts and drives, everything seems good so far. The ESS is such a useless system. Just need to by an Auto Start Stop Eliminator of some kind now.

Smart Stop Start module.

 

[kakwvu]

Smart Stop Start module.

ymmv, but having one installed in my previous ‘18 JLR resulted in the “pull over now due to emergency engine shut off” error that’s been posted about before. I removed it and never got it again. Dealer scanned and scanned for codes and couldn’t find anything.

 

[Heimkehr]

Just need to by an Auto Start Stop Eliminator of some kind now.

This one has worked flawlessly -- no CELs or anything else -- since I installed it immediately after driving my new Jeep home.

The Tazer device provides similar functionality, but at a considerably higher buy-in. Granted, it provides a variety of programming functions for the Wrangler owner.

 

[cpawlFL]

ymmv, but having one installed in my previous ‘18 JLR resulted in the “pull over now due to emergency engine shut off” error that’s been posted about before. I removed it and never got it again. Dealer scanned and scanned for codes and couldn’t find anything.

You had the Smart Stop Start brand that had trouble or a similar device. I ordered a Smart Stop Start Friday. I saw it recommended a few times in this thread.

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