HELP... Need some advice

[BradfordKnight]

Hello and good day to all... well, it hasn't been that good, thus why I'm asking for help!!!

So... first of all, I suspect that both my main and secondary batteries have gone - toes up. 2018 JL Rubi w/ 70k miles... it wouldn't be a great surprise.

I can jump it and it'll run - the alternator reads 14.5-14.6v and tests good. Turned off - and I'm reading 10.7v even after I let it run for 30+minutes.

Here's the kicker though - and what I need help with (please God, someone tell me I'm way over analyzing this) - but after I jump it, and let it run... pressing the break and/or turning the steering wheel enough to engage the power steering causes the engine to lug and/or the whole engine to stall and I can watch the voltage drop to <10v. Does it sound like there's something else hairy going on with the whole electrical system - or could the fact that the batteries are shot be the root cause??? Also... with the hood up - after it dies, and while the ignition is still on, I can hear a high pitch whine coming from the area of the electric power steering pump (and that COULD just be a motor that's mad at being undervolted)

BTW, Saturday it started and ran just fine - Sunday... wouldn't start. Jumped it Monday AM and went to work and didn't notice anything - Monday PM on the way home it stalled twice, while turning and breaking... luckily I had a full charge on my portable battery!!

I just need a second opinion before this breaks my bank account!

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[BDinTX]

I think it's just your batteries. I had a situation a while back (resolved by code update) that showed a similar drop in voltage while turning and braking.

 

[jeepdriver99]

I agree with BDinTX. It's probably time to replace them. I just replaced both of my batteries in my 18 JLR.

 

[John VonJeep]

Well, it’s relatively cheap and relatively easy to replace the batteries. Do that and report back. Odds are that’s all it is.

 

[JEEP4U]

Bradford, Test both batteries. Replace if they are bad or marginal.....winter is coming.

 

[Rhinebeck01]

@BradfordKnight

Please pay it forwards .....

Do come back here and post/tell other's about your journey in regard to replacing the 2 batteries on your JL. Other's can learn from your experience with this...

Either that or I send you a bill in the mail for 55 min. , 18 sec. of my time....

 

[DavidArmen]

It looks to me like your batteries are totally shot. So shot that even the alternator isn’t able to bring them back. The vehicle will not function properly with a totally dead battery even if the engine is running and the alternator is providing power. There will be scenarios where the jeep needs to draw more power than the alternator can provide, it draws this power from the battery.

 

[BradfordKnight]

Well, first of all - huge shout out to Bill @Rhinebeck01 - thank you sir for your time!!

Yes, I swapped both batteries - and again, thank you Bill for taking the time to give me some pointers and saving me a LOT of time. Had to get one battery from OReilly's and one from Autozone - but got them both in and all the problems have at least so far gone away. I took a little drive to put some juice into the batteries and will put them on a trickle charger over night.

That said... there is a youtuber out there that did a battery swap - I won't mention his channel - but don't go at the auxiliary battery from the top through the PCM - there are three bolts under the battery that will drop it down so that you can get to it. Yea, I had to peel the wheel well liner back to get to it... I could actually get to the battery box by just pulling the liner out of the way, but there was no way to get to the terminals, so I popped a few rivets and then put them back in place really easily with the cheap rivet gun from Harbor Freight - again, thank Bill for that bit of advice!!!

The main battery was pretty straight forward!

Oh... and Bill even gave me the right batteries - brands and part numbers will vary, but the specs are:

Main Battery - AGM - Group 94R H7 800+CCA
Auxiliary - AGM - Group S400 - AUX14 200 CCA

Again, I can't thank Bill enough for his time... and going forward - if anyone has any questions, feel free to ask, but Bill is the expert!

 

[Jamrock]

Remember to always change both batteries at the same time. The weaker one tends to drain the stronger one.

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