Only getting power from the auxiliary battery only

[jeepgirl4life17]

My jeep was running just fine until we cut it off and went in a store and came back out and it wouldn't start back up. Now we are only getting power from the auxiliary and not getting any power from the main battery and we replaced both batteries at the same time and we changed the alternator and still nothing. It will crank up if you put the jumper cables on the aux battery but then die if you take the cables off. We are not getting any power at all from the main battery. My Husband is about ready to set the jeep on fire. we have tried everything possible. Are there any recalls with the 2018 Jeep Wrangler Jl?

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[Bob Burd]

Sounds like you may have blown the N3 fuse on the high current fuse array.

 

[Reinen]

Yeah, you probably blew the N3 fuse. Likely when you were changing batteries, it's not hard to do. With the dual batteries, cables removed from the battery may still be powered by the other battery. If they're shorted it will pop N4 and the batteries won't recharge properly.

Follow this video of how to test your high capacity fuse array.

If N3 is blown and you have nothing on N4 you can move the cable from N4 to N3 as they are the same capacity. That will last you until you pick up another fuse array.
It's part number 68368853AA.

 

[Rhinebeck01]

@JeepGirl4Life

I see you have a 2018 JL...

A 2018 JL assembled early in the 2018 model year, deals with a depleted Aux battery differently then JL's assembled after that time.. On many early model year 2018's, if the Aux battery is depleted, the 2018 JL will not try to start. Again, it will not try to start.

2019 and newer JL's left the factory with a pcm update, and thanks to that update.... the JL if the Aux battery is depleted, will make a 2nd start attempt.

In regard to a TSB you were seeking..... Forum search TSB 18-092-19. since you own a 2018 JL. IF you have the pcm update mentioned in that TSB your 2018 JL will behave like newer model year jL's and it will start on 2nd attempt if the Aux battery is depleted.

OK... about your JL. .... you have given little info but my guess is your early model year, 2018's main and aux battery finally aged out and you had a no start event when you went to the store thanks to battery(2) depletion.

So, your husband bought two new batteries and installed them on your 2018 JL. While installing the Main battery your husband inadvertently blew fuse N3 in the high amp fuse array. This happens (can happen other ways also) when the bundle of wires you remove from the main battery positive side accidentally touches something metal. If fuse N3 in the high amp fuse array found in the power distribution center) is blown, the alternator can no longer charge the Aux battery. Yes, the alternator still charges the main battery but no longer charges the aux battery..

With all that I mentioned in mind, I'm speculating the Aux battery presently on your JL is depleted to a point that your early model year assembled 2018, detects Aux is depleted and thus will not try to start.. When your husband put jumper cables to the aux battery" the JL see Aux has enough 12v and it does it's start attempt and starts..

How should you and your husband now proceed.. To test my speculation.... Have a fully charged Main battery and a fully charged Aux battery installed on your JL. Now, move N3 on the high amp fuse array to N4 on the high amp fuse array.. (you can forum search using the words high amp fuse array) Assuming my speculation above is correct your 2018 JL will now start up when you go to start it.

If the JL starts and seems aok dual battery wise, you can drive around and use your JL with N3 on N4 in the high amp fuse array. No harm no foul doing that. Do though, buy a new fuse array ($50ish) when you can and install it. Do forum search as there are 2 different high amp fuses arrays that could be used. IF your JL has tow package installed, it will use a different high amp fuse array then a JL that does not have the factory tow package.

In closing... it's a simple process to do as I mention above to see if it remedies your issue. Do give it a try and let us know how you make out.

https://www.jlwranglerforums.com/forum/threads/alert-high-amp-fuse-array-related.65085/

https://www.jlwranglerforums.com/forum/threads/loud-fan.114234/post-2374594

https://www.jlwranglerforums.com/fo...nd-n3-fuse-blown-replaced-blown-again.117638/

 

[jeepgirl4life17]

Yeah, you probably blew the N4 fuse. Likely when you were changing batteries, it's not hard to do. With the dual batteries, cables removed from the battery may still be powered by the other battery. If they're shorted it will pop N4 and the batteries won't recharge properly.

Follow this video of how to test your high capacity fuse array.

If N4 is blown and you have nothing on N3 you can move the cable from N4 to N3 as they are the same capacity. That will last you until you pick up another fuse array.
It's part number 68368853AA.

Thank you so much

 

[jeepgirl4life17]

@JeepGirl4Life

I see you have a 2018 JL...

A 2018 JL assembled early in the 2018 model year, deals with a depleted Aux battery differently then JL's assembled after that time.. On many early model year 2018's, if the Aux battery is depleted, the 2018 JL will not try to start. Again, it will not try to start.

2019 and newer JL's left the factory with a pcm update, and thanks to that update.... the JL if the Aux battery is depleted, will make a 2nd start attempt.

In regard to a TSB you were seeking..... Forum search TSB 18-092-19. since you own a 2018 JL. IF you have the pcm update mentioned in that TSB your 2018 JL will behave like newer model year jL's and it will start on 2nd attempt if the Aux battery is depleted.

OK... about your JL. .... you have given little info but my guess is your early model year, 2018's main and aux battery finally aged out and you had a no start event when you went to the store thanks to battery(2) depletion.

So, your husband bought two new batteries and installed them on your 2018 JL. While installing the Main battery your husband inadvertently blew fuse N3 in the high amp fuse array. This happens (can happen other ways also) when the bundle of wires you remove from the main battery positive side accidentally touches something metal. If fuse N3 in the high amp fuse array found in the power distribution center) is blown, the alternator can no longer charge the Aux battery. Yes, the alternator still charges the main battery but no longer charges the aux battery..

With all that I mentioned in mind, I'm speculating the Aux battery presently on your JL is depleted to a point that your early model year assembled 2018, detects Aux is depleted and thus will not try to start.. When your husband put jumper cables to the aux battery" the JL see Aux has enough 12v and it does it's start attempt and starts..

How should you and your husband now proceed.. To test my speculation.... Have a fully charged Main battery and a fully charged Aux battery installed on your JL. Now, move N3 on the high amp fuse array to N4 on the high amp fuse array.. (you can forum search using the words high amp fuse array) Assuming my speculation above is correct your 2018 JL will now start up when you go to start it.

If the JL starts and seems aok dual battery wise, you can drive around and use your JL with N3 on N4 in the high amp fuse array. No harm no foul doing that. Do though, buy a new fuse array ($50ish) when you can and install it. Do forum search as there are 2 different high amp fuses arrays that could be used. IF your JL has tow package installed, it will use a different high amp fuse array then a JL that does not have the factory tow package.

In closing... it's a simple process to do as I mention above to see if it remedies your issue. Do give it a try and let us know how you make out.

https://www.jlwranglerforums.com/forum/threads/alert-high-amp-fuse-array-related.65085/

https://www.jlwranglerforums.com/forum/threads/loud-fan.114234/post-2374594

https://www.jlwranglerforums.com/fo...nd-n3-fuse-blown-replaced-blown-again.117638/

Thank you so much!

 

[Rhinebeck01]

Thank you so much!

@jeepgirl4life17

Just know that the info given in 2 earlier posts from other forum members mentioning N3 and N4 is unfortunately, incorrect info.

Both stated N4 was blown and should have said N3. Also, one gave info suggesting moving N4 to N3 which is incorrect.

N3 is the fuse that gets blown and causes alternator not to charge the Aux battery, not N4.

The info in my post is correct / spot on.

Hopefully, incorrect posts get corrected.
@Reinen
@Bob Burd

 

[Reinen]

@jeepgirl4life17

Just know that the info given in 2 earlier posts from other forum members mentioning N3 and N4 is unfortunately, incorrect info.

Both stated N4 was blown and should have said N3. Also, one gave info suggesting moving N4 to N3 which is incorrect.

N3 is the fuse that gets blown and causes alternator not to charge the Aux battery, not N4.

The info in my post is correct / spot on.

Hopefully, incorrect posts get corrected.
@Reinen
@Bob Burd

Yeah, I got thrown by the first post. Corrected.

 

[rcadden]

Man this forum is great. The depth/wealth of knowledge, along with the friendly nature and simple desire to help each other.

Jeep on, friends.

 

[jeepgirl4life17]

I definitely like having so many people to talk to about the issues with jeeps!

 

[jeepgirl4life17]

Yeah, I got thrown by the first post. Corrected.

Thank you yes its was n3 fuse! But honestly we just did away with aux battery all the way around which i never used the auto stop and start i wanted to but i just don’t care for it. If i was to design a jeep it wouldn’t have to to even start with! Seems like its just cause more problems all the way around! Plus i put a taser mini in my jeep to completely turn that off when you crank the jeep

 

[Maverick909]

god i love this forum. No need for my reply but glad you got it squared away.

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