Auto Start still working after disconnecting

[THAW]

Maybe when I charged the main battery, thats what made it start working?

That's exactly what happened.

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[agpthng]

I had nothing but problems with the Auto Start/Stop feature. When the aux battery wasn't working neither was my jeep. The main battery wasn't taking over the aux battery function of the auto start stop feature. I always shut it off after I start my jeep. But when the aux battery was having issues, I could be driving down the road at 65 mph and my steering would lock up, all the idiot lights came up along with the warnings telling me that the start stop system needed to be serviced. So be careful out there if it's acting up. I had to go to the dealer and they read my journal of events with what was happening with it and traced it back to the aux battery failing.

 

[aeonixx1001]

Forgot: This is 2019 JLU. 3.6

Try pulling the Power control relay fuse (F42)

 

[Beach Nut]

Heres something that is blowing my mind. About a year ago I had the aux battery go bad. Instead of replacing it, I unhooked the ground and taped it up. No issues other than the light on the dash telling me it was not working. The other day, the jeep wouldn't start. I charged the main battery and got it started. Took it to O'reilly where i got the original main battery so they could test it and replace if needed since it was under warranty. They hooked everything up and said the battery was fine and the charging to it from the jeep was fine. So, I went on. Yesterday I was sitting in traffic and the jeep shut off. I thought it died on me, but realized it was just the auto on/off. I pushed the button to turn it off, and it was fine. I thought it was a fluke and I popped the hood to check, and the ground is till taped off and not attached. Tried it again later in the day and when I stopped at a redlight, sure enough the auto start/stop engaged.
Thoughts are: if I didn't detach the correct terminal, how was the jeep running on the aux battery for over a year? Or how did the ESS just start working all of a sudden? I don't ever hit the button to turn it off, because it has never worked before. But now I have to hit the button every time I start it up now. I'm really wondering how this is happening.

Did you pull the # 42 fuse?

 

[azjl#3]

Not a fan of autozone and such battery testing devices. I dont think they work right, and they are not trained.

Had my dad's old grand marquee battery tested, guy said it said 42%, good to go, I said no not really, what voltage. He says 11.4. You really think 11.4 is good enough? Shrug

Anyway, my rule of thumb, anything below 12.4 after sitting overnight, is a bad battery.

 

[jeremyirick]

Did you pull the # 42 fuse?

Yes. The ESS system didnt work and the warning light was on for about a year, so I thought the aux battery controlled it. But I charged my main battery the other day after it was cold weather for a few days here, and now the ESS system is back on. Not a big deal to push the button to turn it off, but was confused as to how it was working with the aux battery not hooked up. But seems like the main battery that is now fully charged, is powering the ESS system.

 

[Beach Nut]

I disconnected mine too, but now I got a “Service Air Bag” alert…WTF?

 

[Bayrat]

After disconnecting the SS battery, pull the connector under the hood, on the bottom of the plunger, closest to the driver side. That will disable SS for free. All you'll have to deal with is the usual SS unavailable light on the dash.

 

[aeonixx1001]

Do you mean the Hood Safety switch, there are two?

 

[KCSgtMaj]

Ghosts in the machine!

 

[Coreyb516]

So I can remove the aux battery, and the main battery will handle everything? I always thought the ESS was dependent on the aux battery alone, since it didn't work anymore when I removed the aux. Maybe when I charged the main battery, thats what made it start working?

 

[aeonixx1001]

Do you have a Tazer? Did you pull fuse 42 (Power control relay)

 

[Bayrat]

Do you mean the Hood Safety switch, there are two?

The switch closest to the driver side.

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