Dreaded Auxiliary Battery

[Lawman]

Question, a few weeks back I disconnected the correct negative cable, taped it up and zipped tied it back out of the way. I then pulled fuse F 42 and have not had any issues. Today when I started my Jeep the avenger light came on?? I drove for a bit and then pulled over, shut it down and waited about 30 seconds started it back up and the light did not come back on. Was this the computer randomly looking for the auxiliary battery? Please don’t hate me, I’ve looked through a lot of the posts for similar questions. Has anyone else had this happen?? Thanks

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[Mr._Bill]

That shows that the Main Battery was below an acceptable charge level. It still does the Aux Battery test at every startup. With the F42 fuse pulled, it is doing the test on the Main Battery. Either the Main is on the way out, or you're not driving it enough to keep the battery charged.

 

[Metalhead]

Is that all you have to do to eliminate the aux battery is disconnect neg cable and remove fuse?

 

[Mr._Bill]

Is that all you have to do to eliminate the aux battery is disconnect neg cable and remove fuse?

That takes it out of the circuit, so it is no longer being used. It does not disable ESS.

 

[Metalhead]

I have ESS disabled anyway.

 

[Andy29847]

I have ESS disabled anyway.

Even with ESS disabled, the Jeep system will test the battery at start. When the battery falls below programed levels (~12.4vDC), you will get a warning (Avenger) light. When this first happens, the light will go out after the battery is charged (normal driving). The battery should be good for many more miles. You may can judge how good the battery is by how long it takes the waring light to go out after starting.

The Mopar batteries in my 2020 JLU were replaced under warranty 2-1/2 years ago. I have been driving with both new batteries connected and ESS disabled since then. When I got the warning light the first time, I decided to remove both Mopar batteries and replace the big battery with an Everstart (Walmart) Platinum H7 battery. The removed main battery tested at 12.8vDc after charging and sitting overnight. The aux battery tested at 12.7vDC. Since the batteries were testing good, I listed them on Facebook Marketplace and sold them. The sold the first day for $40.

 

[Chasm]

Please don’t hate me

Hahahah, I think we all know the people you're speaking to with that!

 

[Lawman]

Thanks so much guys!! That makes sense!! I appreciate the help. It is colder here now so I will keep an eye on the main battery.

 

[Stan H]

Thanks so much guys!! That makes sense!! I appreciate the help. It is colder here now so I will keep an eye on the main battery.

It probably just days from being too dead . Trust me I had to get jumped once. They literally will die outta the blue . Started up just fine drove to a site and went to restart and well it was deader than 4 oclock

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