Hello everybody. I wanted to subscribe to the AUX input on my Blaupunkt RD4 with MP3 with my Citroen C4 and was in my workshop. The changer is unlocked and I have connected a connector with 3.5mm jack. I can not access it, however. Is it possible that does not recognize the radio this cable and I have to switch to a USB interface of Yatour, anycar or other? Despair slowly and do not want to rely absolutely on another radio. I hope you know about it. 1000 thanks in advance.