Split Second Starter Engagement

[RustyNut]

2018 Wrangler Unlimited Sahara JL
3.6L 8spd Auto 12,000 Miles

Went to start and starter will engage only for a split second. Dash panel display blinking, then settles down. Try to start again and starter will engage only after releasing finger from starter button and only for a split second. Did battery check on both batteries and fully charged. Buzzing sound and dash panel lights will not turn off. I disconnected #1 at the main fuse/relay panel to shut off buzzing and lights.
Has anyone experienced this problem?
Bud

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[Rhinebeck01]

@RustyNut

You say you have 12,000 mi. on your 2018 JL. Did you purchase less then 36 months ago?

This "battery check on both batteries".... how did you do that.... did you load test both batteries?

How did you "disconnect #1" ?

Anyway, you are undoubtedly facing what many other 2018, JL owner's will be experiencing this year/2021.

Your batteries have aged out and are iffy/shot and your use of the JL is very little so battery(s) are depleted...

Read all my responses to another 2018 owner yesterday:
https://www.jlwranglerforums.com/forum/threads/battery-issue-no-start-after-an-alignment….75012/

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[Rhinebeck01]

@RustyNut

Should have mentioned.... my guess is you do not know how to separate out the 2 batteries in your stock dual battery system.

Your issue probably is that your Aux battery is depleted or dead..

And since you have a 2018 JL, it ... your 2018 JL, will not try a second time to start if the Aux battery is as mentioned.... (unlike 2019 and newer JL's) won't try a second time even if the Main battery has enough charge to start the vehicle..

Anyway, your 2018 , undoubtedly needs two new batteries.

 

[RustyNut]

@RustyNut

Should have mentioned.... my guess is you do not know how to separate out the 2 batteries in your stock dual battery system.

Your issue probably is that your Aux battery is depleted or dead..

And since you have a 2018 JL, it ... your 2018 JL, will not try a second time to start if the Aux battery is as mentioned.... (unlike 2019 and newer JL's) won't try a second time even if the Main battery has enough charge to start the vehicle..

Anyway, your 2018 , undoubtedly needs two new batteries.

Thanks for the fast reply. Bought this Wrangler used two months ago from out state dealership. Removed batt cables from upper and lower batts, charged to full, used my Sun battery load tester. Upper batt ck good, lower 10.5, I’ll heed your advise and replace both.
Thanks again. Bud

 

[Rhinebeck01]

Thanks for the fast reply. Bought this Wrangler used two months ago from out state dealership. Removed batt cables from upper and lower batts, charged to full, used my Sun battery load tester. Upper batt ck good, lower 10.5, I’ll heed your advise and replace both.
Thanks again. Bud

@RustyNut

Aux is shot and Main is probably close to shot..

Replace both the same day... I have made many a post of batteries to use and how to easily access the Aux. Do a forum search and read read...

Caution.... Do NOT disassemble the power distribution center (PDC) to get to the Aux battery!!! Could be a costly mistake for you.

Also, research how not to damage the High Amp Fuse Array.... easy to damage same when fooling with the Main battery connections.

Anyway read all of this thread... You will need to order fender flare clips or buy a rivet gun and rivets... depends on which of 2 ways you proceed to remove the Aux battery.
https://www.jlwranglerforums.com/fo...ent-the-easy-way-pull-the-fender-flare.56807/

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[RustyNut]

Thanks Bill
Looks like I have some good reading info to go through. I’m summering up here in a small town in RUAL MN and I’ll do some research logistics on battery choices.
Thanks again for your helpful and much appreciated advise.
Bud

 

[RustyNut]

Hello Bill
OK, bit the bullet and purchased both batteries from Jeep dealership. Installed batts and same problem, depress brake, push starter button, 3 second delay and just a bump from starter. Had wife do start procedure while I watched engine damper and it moved about a 1/4". Switched relays in PDC with other relays and no difference. (starter relay) (start/stop relay). Tried the by-pass jumper set up to no avail. I'll try some starter-starter solenoid diagnostics, those little buggers are pretty well jammed up there.
Bud

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