Hi all. I have a 2003 base model Cooper. It has the stock radio with no auxiliary input. I know that there are many harnesses to add Aux IN to the radio, but I've heard that there are some radios that will not work. Even if the harness fits, there's no Aux input. My radio cycles through FM/AM and cd. There is no aux option. Does the harness need plugged in before the "AUX" option is added to the cycle?