Yes you need to start them or disconnect the battery.All the electronics drain the battery.Mopars when the battery gets low or bad plays havoc with them.He probally plugged into the acc port inside and jumped the batt.Keep leaving it sit with the batt hooked up and it will be jumk soon.Had a guy with a Caddy that just couldnt accept the fact that he couldnt let it sit for weeks and the batt wouldnt die.We replaced the batt twice even though after a charge it tested good.Last time told him either use a disconnect or start it and let it run.Rocky