The dreaded dead battery happened to us. Went on vacation for a week without our Smart and the battery was dead when we got back.
I hooked up the charger to the battery (without removing it from the car) and the radio came on. I thought it was odd because the key was not in the car. I turned it off and thought nothing about it.
After the battery was charged, I started the car and everything seemed normal. Turned it off, removed the key and pressed the radio button and the radio came on. I don't recall trying this before and wondered if others have this same issue. We have a appointment for the technical changes, but already have the upgraded battery.
Can you turn on your radio without the key inserted (car not running)?
Thanks,
Don