2018 Jeep Wrangler JL wont start Aux Battery Disconnected Share with Everyone You know

With the Auxiliary battery disconnect will the Jeep JL Wrangler start? With the Main battery disconnected and the Aux battery connected will the 2018 Jeep JL Wrangler Start? You'll never believe it!!

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[BrandonHaneline]

for all your Jeep Parts, Accessories, and just cool Jeep stuff.

[lrncephil]

Interesting. In my girlfriend's 2018 compass sport, her auxiliary battery died under warranty but the dealership didn't have any in stock at the time. She wasn't bothered because she hated the stop/start feature lol. Anyway, her jeep still started with only the main battery without any issues. However, after a few months the main battery ended up dieing. We changed it out, everything was good for two days then it died and wouldn't start. We realized without the aux battery functioning, it was draining the main battery. That's most likely why the main battery died soon after. We replaced the aux battery and everything was right with the world.

[charliedee]

My explanation of Jeeps crazy wiring. I worked at Jeep for quite a few years as a Chassis Designer. The great majority of the Electrical Engineers are from India, I have no beef with that. However if you see any pictures of the cities in India take a look at the wiring on the poles. You will see exactly why Jeeps, and most other American vehicles have SO MANY electrical problems.

[billyhw]

So how would you jump start the jeep if A. The main battery was dead versus B. The small aux battery was dead? Is there a different procedure?

[djonesey]

Please Mr. Halon: educate us on how, if it's even possible, to jump start a JL were either or both batteries are dead!!! Where do the cables go? Do you need special hardware..do you need to tabl T5 in the PDS???!!!

Thank you!!!

[georgea.]

Next time your main battery dies - Get yourself a good powerful, AGM main battery. Disconnect the aux battery’s negative cable, wrap it up good and secure it somewhere out of the way. Pull fuse number 42. No more start/stop and no more issues of the aux draining the main. You now have a normal functioning Jeep and no longer have to worry about this shit. YW. . .

[go_dawgs_]

This helped me identify the troubles with my moms 2018 wrangler, thank you so much!

[antifederalist]

Can you post a video for the proper procedure to jumpstart a JL?

[markrobert]

The aux battery powers the computer system and is strapped to the main battery possibly with a diode block. Discounting the aux battery disables the starting system and computer.

[holder]

A couple of observations after looking over the schematic.

The Aux battery has 2 positive connections... one on C5 (PDC?) and the other on C3 (Power Control Relay)
This shouldn't matter, however because the negative connection was removed and that opened the circuit, unless current was still flowing thru the intelligent battery sensor somehow.

The main battery cannot provide power to the starting system until the Stop/Start relay has closed, and I believe the JL uses the Aux battery voltage to close that relay.

I would be interested to see if removing only the negative wire from the Aux battery would allow a crank, if so, then either the connector you removed from the PDC feeds other circuits in the system, OR there is still current flowing into the ground connection from the Aux battery.

I'll say it again, awesome videos man, and I like your approach to things.

[legion]

Trouble with my Jeep 2018 Wrangler, One day got in the truck push to break Pedal, push The start button, just clicks, break pedal doesn't go all the way down like It used to, Batteries good, There's something I'm missing I've check fuses what else could be. It's Christmas and my family needs this truck, thank you every one

[briandell]

I think your problem is that you disconnected the positive terminal to the fuse block which works with the computer. I, and many others have pulled the auxiliary battery, taped off the ends, then pulled fuse 42 which has to do with the computer and the start stop function, your Jeep should start, countless people have done this. It is a bad design, because if the auxiliary battery goes dead, which is very common it kills the main battery or make your Jeep do crazy things, plus not start. In saying this, I am NOT a mechanic, I do not play one on TV, I am only passing on information that i have learned from others who have had the issue with the small battery killing the main and stranding them and NOT knowing how to fix. I have also installed a Auto Start/Stop Eliminator which holds the last input to the button on the dash.

[ajphillipsjeeps]

I think the difference is where you sdisconnected at. I think if you were to disconnect at the small battery itself while leaving the cables connected to the rest you might get a different result.

[danielsmith]

Why not just remove the auxiliary battery completly by connecting the aux positive cable to the main battery positive cable then completly removing the aux ground cable( It wont be needed any longer) therefore completly eliminating the aux battery. I would only do this if you do not use the stop start system but the stop start system will still function if you want it to.

[Cardiff]

Always and I mean always disconnect the negative terminal FIRST!

[jimmyfishburn]

Love my 2018 JL But. Saving you for Ref.

[superchargedgtp]

Love these videos and keep em coming! With some additional knowledge and confidence about the new JL we purchased a White JL Unlimited Sport this weekend with the 24S, Auto, Hardtop, and Tech package. Loving the new Wrangler already!

[stevewaid]

The number 5 fuse on the high current fuse array is for the rad fan

[RafaQP]

Could it be because of the Auto start bottom is still working?

[richardslosar]

Hi I have a 2021 JL 2 dr wrangler V-6 Manual transmission. If I kill the engine while driving their is a 75% chance I can not start the jeep again. What i have learned is that I disconnect the last large wire from the fuse box which in someway resets the electronics where i can start it again. dealer were of no help because they could not figure it out . So I do not have to get out of the car and do this procedure to get it started again I installed a electronic devise to the large cable going into the fusebox that will turn it on and off from the cabin using a FOB. Also note that when this happens and i disconnect the positive cable from the big battery and reconnect it still does not start or even crank. the only solution is pulling the last large wire off the fuse block are, thats is the wire that is closest. to the front of the jeep. Any ideas what is going on here. It is a manual transmission ! Thanks