Ravinghill

Hi there - just got a 2010 dodge journey 2 days ago and have this question. I plugged an iPod classic in via the integration cable and it all worked fine. Happy days I thought but I left it connected to the cable overnight and came out next morning to find the battery in the car completely dead. Dies anyone know if the charging function of the cable continues with the key off or does it shut off with the other functions of the car. Thanks