WRANGLER JL WILL START & RUN WITH BATTERY REMOVED

mgroeger

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On a JL/JLU .... To kill power from the Main battery and the ESS battery:

JLpower.jpg
Twice I've had to disconnect the three negative battery terminals. Each time terminal #2 (from the pic) sparks like heck when you touch it back to the bolt to thread it on. I can here a clicking noise coming from the black box right next to it.
Has anyone experienced that?
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FatBoy01

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@mgroeger

I do not have a JL yet.

Normal to see this ....... is what I can tell per posts here, a YouTube video I saw and a tech I asked at the stealership a couple of weeks ago.
 

FatBoy01

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Just wanted to clarify some info I posted earlier in this thread. I had placed an incorrect pic showing terminals in the post as N1 and N2 which they weren't.

Yes, the negatives are both common but the positives go to two different posts (N1 & N2) in the power distribution center. There is module / ESS relay that controls when to use the ESS and when not to use. N1-Main battery, N-2 ESS battery.

Important to know: You can have a fully charged Main battery and if the ESS battery is either dead or disconnected, the JL will not start, even though the main battery is fully charged. On the other hand, if the main battery is missing or dead the ESS battery can start the JL/JLU.

If you wanted to isolate the positive side, disconnect N1 & N2 in the power distribution box.
N1-Main battery, N-2 ESS battery.
disbox2.jpg
 
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BillyHW

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Just wanted to clarify some info I posted earlier in this thread. I had placed an incorrect pic showing terminals in the post as N1 and N2 which they weren't.

Yes, the negatives are both common but the positives go to two different posts (N1 & N2) in the power distribution center. There is module / ESS relay that controls when to use the ESS and when not to use. N1-Main battery, N-2 ESS battery.

Important to know: The ESS battery is what actually starts the JL/JLU, not the main battery! You can have a fully charged Main battery and if the ESS battery is either dead or disconnected, the JL will not start, even though the main battery is fully charged.

If you wanted to isolate the positive side, disconnect N1 & N2 in the power distribution box.
N1-Main battery, N-2 ESS battery.
disbox2.jpg
That doesn't sound right at all.
 

FatBoy01

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That doesn't sound right at all.
Daaaah, l must be making it up then. How about you come up with something different Einstein.
 

BillyHW

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Daaaah, l must be making it up then. How about you come up with something different Einstein.
Does it really make any sense that in places that get cold winters they'd use a battery with ~200 CCAs to start a vehicle instead of a battery with ~700+ CCAs?
 

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Does it really make any sense that in places that get cold winters they'd use a battery with ~200 CCAs to start a vehicle instead of a battery with ~700+ CCAs?


My wording was incorrect. I edited / reworded that post so hopefully it is conveying what I meant to convey.
After I reread my post I see why you questioned it..
 
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rizej

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Twice I've had to disconnect the three negative battery terminals. Each time terminal #2 (from the pic) sparks like heck when you touch it back to the bolt to thread it on. I can here a clicking noise coming from the black box right next to it.
Has anyone experienced that?
What order are you reconnecting the battery terminals back together? Maybe a different order would stop the sparking
 

mgroeger

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Another member confirmed this to be "normal". He had seen a YouTube video and spoke with a tech at the dealership and they saw the same thing.
 

NFRs2000NYC

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So does the Jl then have a dual battery system from the factory? If the main one is killed the smaller one with start the jeep, or is the issue the fact that there is no isolator, so if an accessory is draining the juice, it wont stop at the main battery, and it will drain them both?
 

BillyHW

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So does the Jl then have a dual battery system from the factory? If the main one is killed the smaller one with start the jeep, or is the issue the fact that there is no isolator, so if an accessory is draining the juice, it wont stop at the main battery, and it will drain them both?
Kind of useless if you can't start the car if the small battery is drained for some reason. This boggles the mind.
 

JIMBOX

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Well, the owners manual shows using a jumper cable set-up, as we have for over 85 years and connecting connectors to the MAIN PRIMARY battery +/- and making no other adjustments/conns/disconns--

Just follow the safety conditions with ign sw/jumper cable sequence--start booster car/start jeep/disconnect (follow sequence)/drive jeep away--go home tell wife because of the trouble, you have to have a HEMI/LS swap as soon as possible !

Whatever

JIMBO
 

BillyHW

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Well, the owners manual shows using a jumper cable set-up, as we have for over 85 years and connecting connectors to the MAIN PRIMARY battery +/- and making no other adjustments/conns/disconns--

Just follow the safety conditions with ign sw/jumper cable sequence--start booster car/start jeep/disconnect (follow sequence)/drive jeep away--go home tell wife because of the trouble, you have to have a HEMI/LS swap as soon as possible !

Whatever

JIMBO
Yeah, I checked the manual too and the jumpstart procedure appears to be the same as every other car ever made since I was born at least.
 

Spotscrib

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Twice I've had to disconnect the three negative battery terminals. Each time terminal #2 (from the pic) sparks like heck when you touch it back to the bolt to thread it on. I can here a clicking noise coming from the black box right next to it.
Has anyone experienced that?
How long before you lost complete power I just did the same and I still have power
 

mgroeger

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After disconnecting the THREE negative battery terminals I lost power immediately.
 
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