Heading to Moab Wednesday and Jeep will not crank!! Need Input!

[Sprint7]

I am leaving with a group of guys Wednesday morning for a 11 day trip to Moab / Colorado. I ran the battery down a few times and wanted to be proactive so i decided to change both of my batteries before the trip. Everything with fine with the change until i tried to crank the jeep and nothing!
I have 12v because the dome light, dash light up, even the ARB has power. When i try to hit the start button it has no effect. Does not say FOB not detected. Tried to start by pushing with the FOB, but nothing. Another note is that the jeep does not appear to pick up either FOB. Will not lock/unlock doors, nor does the panic button work.

I am open to any and all suggestions. Panic is about to set in!

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[Medsker]

That sucks! I know you just installed the battery but have you tried unhooking it for a few minutes and then re-hooking it up and see if it does anything? That would be my go-to move if I was having those problems. Good luck getting it going!!!

 

[thecritter]

Not sure about fob not locking and unlocking. Mine did not want to start when new had to press the break pedal really hard to start.

 

[BCalvin]

Start checking fuses and relays. When you disconnect just the ground post on the main battery, the circuit is still hot.

Did you follow this order?

 

[Sprint7]

No I didn’t. I follow a video from “the other guy”. It was in the internet so I assumed it was true! I will start checking in the morning.

 

[Ntegtmeyer]

Make sure both batteries are properly connected and IBS is secure.

 

[Sprint7]

Make sure both batteries are properly connected and IBS is secure.

I can rule out the IBS as a swapped one from another JL and it did not have any effect. I am going to remove all of the stuff around the aux battery again to take another look at it. I also checked every fuse in the panel and no issues. Not sure how to check a relay but that will be next.

I believe that the Aux battery is correct because even with the main battery out of the jeep i have dome lights, some dash lights, etc.

For some reason it is not picking up the 12v’s from the main battery! I have to be missing something pretty simple but I’m just not seeing it. What would keep the main 12v battery isolated from the jeep when properly installed?????

 

[DOOKEY]

Did you take the cover off the posts?

 

[DOOKEY]

 

[MarkY3130]

I’ve never removed the batteries so I’m likely speaking out of turn.

When I’ve disconnected the negative cable (main battery) and separated them from each other, it’s killed power to both batteries.

With you having removed the main battery and still having power from the aux battery, is it possible you installed the grounding cables incorrectly?

 

[Sprint7]

I laughed when I saw this but I did go and check. Lol. That’s not the smoking gun!

 

[DOOKEY]

I laughed when I saw this but I did go and check. Lol. That’s not the smoking gun!

Have you thought about putting the stock batteries back in to see if everything works?

 

[aldo98229]

Freud would say you really don’t want to go to Moab.

 

[Cthehentz]

Have you checked the high amp N1-N8 fuses?

 

[jeepoch]

Mike,

Whether or not you're a big Electronic Stop Start fan, the design and implementation of ESS has really complicated the JL ignition system. The most obvious first step is checking the charge on the AUX (smaller) battery. The AUX battery must be of sufficient charge to enable a pre-start relay. This pre-start relay does not engage the starter motor directly but rather closes a secondary circuit which allows the main battery to then engage the starter. It sounds like you're missing this first circuit step.

Are their any hints on the cluster?

Have you tried jump starting? If so, did you leave the jumper cables connected for many minutes before attempting to crank? Recall, these two batteries are connected in parallel. The Main will likely take most of the charging energy up-front, but it's the AUX battery that must be charged in order for the Jeep to start. This will require some charging time.

Lastly, double check all the connections and make sure all the fuse and relays are pushed firmly down and that they make good connections within the fuse and relay module. This is the most likely culprit because you have to move this module out of the way just to gain access to the AUX battery.

Don't panic. Everything was working. It's just now a matter of ensuring everything has been put back together and has sufficient charge on the new batteries. New batteries are not always received fully charged.

You'll get there...

Jay

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