Hi, Sometime ago my HU stopped playing CDs and now I just thought of trying a DIY to add Aux in. But I don't have the radio code with me. It has a bosch unit. Will I need the radio code after I detach the wiring harness at the back of the HU? I'm confused as I expected the HU to ask code when the car's battery was changed a few months ago but surprisingly it didnt. So even if I remove the wiring harness at the back, it wouldnt ask for the code. Can anyone throw some light on this?