2018 JLU Aux Battery problem

[Tiger4Life]

Jeep is in the shop, died last Friday at the light. Wouldn’t start light and warnings all over the place. Got it towed to my mechanic, found the aux battery was bad so they replaced it. Now with new aux battery they crank it up and the aux battery drains in like 10 mins. Any thoughts would be greatly appreciated.

Thx a bunch
Mike

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[aldo98229]

Sounds like something is draining it.

A short somewhere...?

 

[Tiger4Life]

Sounds like something is draining it.

A short somewhere...?

Yeah that’s for sure but what I have no idea. Just started happening this past Friday

 

[aldo98229]

I’ve been seeing LOTS of similar issues pop up recently.

I saw on another forum a fellow who ended having two wiring harnesses behind the dashboard replaced. They had to remove the seats and the entire dashboard to get to them. Everything was covered under warranty, but the bill to FCA was a whopping $4,600!

I guess one of the key weaknesses of JL’s dual battery system is that all that added electrical wiring creates opportunity for shorts to develop somewhere over time.

 

[Tiger4Life]

I’ve been seeing LOTS of similar issues pop up recently.

I saw on another forum a fellow who ended having two wiring harnesses behind the dashboard replaced. They had to remove the seats and the entire dashboard to get to them. Everything was covered under warranty, but the bill to FCA was a whopping $4,600!

I guess one of the key weaknesses of JL’s dual battery system is that all that added electrical wiring creates opportunity for shorts to develop somewhere over time.

Yeah well again it’s a 2018 and I bought it used last year with 36k miles on it in very good condition. Has been great so far but not sure that’s under warranty anymore

 

[aldo98229]

I hear you.

My 2018 has only 15,000 miles and it’s been trouble free. But my warranty ends in November. Seeing these threads has me considering selling the Jeep when the warranty ends.

Good luck.

 

[Paluss]

is the large battery ok? I have changed both batteries in my 2018, the aux about a year ago (start stop would not function) and large battery about 6 months ago, jeep started to crank slow. I believe the batteries rely on both being charged for the system to work properly. Large battery is very easy to replace...

 

[Jebiruph]

Try this https://www.jlwranglerforums.com/fo...on-and-ess-n3-fuse-warning.66247/post-1548290

 

[Tiger4Life]

is the large battery ok? I have changed both batteries in my 2018, the aux about a year ago (start stop would not function) and large battery about 6 months ago, jeep started to crank slow. I believe the batteries rely on both being charged for the system to work properly. Large battery is very easy to replace...

Yeah i changed the main battery last year!!

 

[Tiger4Life]

Try this https://www.jlwranglerforums.com/fo...on-and-ess-n3-fuse-warning.66247/post-1548290

Jeb you think i should bypass altogether from the aux battery ??

 

[kakwvu]

Jeb you think i should bypass altogether from the aux battery ??

This is the way.

 

[SteadyC]

No, the main point to that thread is to see if N3 is blown, resulting in aux battery issues, and to replace N3. Start at post number 1.

 

[aldo98229]

is the large battery ok? I have changed both batteries in my 2018, the aux about a year ago (start stop would not function) and large battery about 6 months ago, jeep started to crank slow. I believe the batteries rely on both being charged for the system to work properly. Large battery is very easy to replace...

You might be up to something.

I replaced BOTH batteries last year and haven’t had any more electrical issues since.

 

[Jebiruph]

Jeb you think i should bypass altogether from the aux battery ??

It sounds like your N3 fuse is blown and if that's the case, you can move the wire from the N3 terminal to the N4 terminal to get power back to the system electronics.

 

[Tiger4Life]

Update: They have a call into the Jeep dealer to find out what to do next. He said they (Jeep Dealer) can't get to it for 3 weeks. He said they can bypass the aux battery, but they want to know what's draining it, because tieing it to the main battery would cause the main to drain and die too.

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