Amazing thing happened. After waiting almost 3 hours for the vehicle, the service writer tells me they ordered an auxiliary battery. I said "the service manager said there isn't one". To which the service writer said they found one under the main battery and it is bad.
Is it under the main battery?
I had a similar issue - but the car occasionally wouldn't start either. Svc Mgr said they tested both batteries and both were bad - just over 2 yrs old on a 2018 JL.....fortunately just under 36k miles so replacing both under warranty