ESS Dash Icon

[davearm]

I disconnected the negative ground to my auxiliary battery and pulled the fuse, but still have the dash icon. I am assuming I did it in the incorrect order. Searched, but couldn’t find information on the proper sequence.
Do I pull the fuse first, or do it after removing the ground? I can’t remember how I actually did it. So if I put the fuse back in and reconnect the ground am I going to need to pull the positive cable too to turn off the light be

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[Flip]

I'm not actually sure but I would do a test run; put the fuse back in and reconnect the negative battery terminal to see if the dash icon clears.

 

[AndySpill]

Provided--as should be the case--that you are doing these two steps with the engine off, which order you do them in is of zero consequence.

After both are completed, on the next cold crank, just prior to the vehicle engaging the starter, your dual AGM battery JL will attempt to isolate the Aux battery to test it for power.

It will silently fail in this endeavor, unable to energize the normally closed Power Control Relay (PCR) that separates the batteries (due to the Fuse 42 pull) and all calls for electrical current from the Aux battery will now be rerouted to all available batteries, which in your case is only the main battery, as you have disconnected the Aux battery's negative cable at the end that connects to the main battery's negative post, and insulated that cable.

I would presume that failure of your ESS off light in the dash to no longer appear might be reflective of a dying main battery, upon which your JL has, none the wiser, effected what it thought was a test of the Aux battery, but couldn't, due to the absence of electrical power to the PCR as a result of the Fuse 42 pull.

 

[davearm]

The main battery is new, I forgot to add that.

 

[AndySpill]

The main battery is new, I forgot to add that.

I hear this, and in light of it might recommend that this new battery be load tested.

Sometimes new batteries are defective and/or aren't delivered fully charged.

It's entirely possible that your new battery passes such tests with flying colors, in which case cause for your defect needs to be directed to some malfunction of your vehicle, but given the less that rare frequency of defective or less than fully charged new batteries, and the fact that they are cheaper to swap out than vehicle parts which may or may not address your issue, I think it makes sense to rule out problems with this new battery first.

Perhaps you have already done this.

Good luck!

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