2020 JL No Start. Guesses?

[Creeker]

2020 JLR 2-Door w/manual, no start, battery dead.
Before I start troubleshooting, any one want to guess what the issue(s) is?
~15 kMiles, lift and other mods, but no Tazer etc.

Hopped in the Jeep today, battery(s) were dead.
No lights on the Jeep dash.
Lights were off, etc.
Last outing was about a week ago (wife drove it).

Thoughts?

Obligatory Jeep action photo

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[RocknJL]

Have the batteries been replaced? If not I’m betting they need to be and the aux battery drained the main as is a common issue. I would strongly suggest eliminating the aux battery as it causes nothing but headache.

 

[#4Jeep 1st Wrangler]

Replaced both of mine under 3yr/36k warranty.... Placing my bets on the batteries...

 

[Ratbert]

No warnings on the dash before it went out? No chance your wife left your aftermarket lights on?

 

[Creeker]

No aftermarket lights.
Measure 3.3 VDC on main battery.
Tried to charge,
Charged for a while then battery charger faulted out.
Got up to about 7 VDC.

Bought two new batteries (main and aux).
Should fix problem.

 

[RocknJL]

It will for a while but the aux system is seriously flawed. It will happen again sooner than later if you leave it in place unfortunately.

 

[Creeker]

Both batteries are original to the Jeep.
I will look into the delete option for the Aux

 

[2019JLUS]

Given the details, the dead battery could be due to a few factors, especially since the Jeep has a lift and other mods:

1. **Parasitic Drain**: Some mods or aftermarket wiring might be drawing power while the Jeep is off. Even if there's no Tazer, other electrical mods could cause a slow drain.

2. **Battery Condition**: Despite the low mileage, the Jeep is from 2020, so if it's the original battery, it might be near the end of its lifespan, especially if it's been sitting for extended periods or through harsh conditions.

3. **Dual Battery Setup (if applicable)**: If your Jeep has the dual AGM battery system, one of the batteries could be failing, which might affect the whole system. A failing secondary battery can sometimes go unnoticed until it affects the primary one.

4. **Grounding Issue**: Check the ground connections, especially with the lift and mods. Sometimes loose or corroded ground connections can cause issues.

5. **Alternator Issue**: If the alternator isn’t charging properly, even short trips might not give the battery enough charge to keep it running.

I’d start by checking the battery voltage and any parasitic draw, then inspect the mods for wiring that could be causing the issue.

 

[Creeker]

Thx for all the help.
Removed the ground cables from the main battery and tried to recharge the main battery again. The battery charger was charging for a while, then the battery charger faulted (i.e., bad battery symbol).

Picked up two batteries (main and aux). Hope to get those installed today.

Will test the alternator/batteries for charging/parasitic draw.

 

[8ball]

Looks like the typical 3 to 4 year window of battery maintenance. Like mentioned there are two batteries.

I plan to swap both mine out with Odyssey AGM’s when I get close to the 3yr mark proactively. About $500 every three years.

Also just looking, I wonder if removing the tire and pulling back the liner without removing it would be an option to getting at the aux battery. Anyways good luck!

 

[Creeker]

Update:
Went to install both batteries.
This process took a couple of days due to other obligations

The Aux battery from Sam's was a little different where the wire lugs mate to the battery, so a couple of lug tabs were straightened.

To install the Aux battery, tried the fender well trick since I have gutted fenders and metal fender lines. This was a huge mistake. The Aux battery came out OK. But installing the new battery was a royal PITA. It was like the wires to the Aux battery could not get positioned correctly back into the hole and the third of the three fasteners for the Aux battery box would not find home. Gave up on that method and removed the fuse box and installed the Aux battery from the top of the Jeep. This is a much better method, IMHO.

Charged up new main battery and installed.

Tried to start Jeep, but Aux did not have enough power. Second attempt, the JL started up great.

Now I am like my ACD... a tired but happy dog.

 

[Creeker]

Got everything put back together. Took the Jeep out for a test ride. So far so good (14.4 VDC on the dash gage). Don't think the Aux battery is charged up yet as the jeep begins to start after the second pressing of the start button.

 

[Bob Burd]

You might check the high current fuse array. You may have blown the one on P3 or P4 (I never remember which it is). Will keep Aux battery from getting charged by alternator.

 

[mwilk012]

You removed the PDC, huge mistake.

 

[gm920]

You might check the high current fuse array. You may have blown the one on P3 or P4 (I never remember which it is). Will keep Aux battery from getting charged by alternator.

N3

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