I have a citroen C4 SX 1.6HDi, with the standard CD player. I was going to change the headunit as i'd done in previous cars i'd owned to one that plays MP3's. However due to some of the diagnostic tools being on the radio head unit itself i thought i might go down a different route. I have a TomTom 910 with has 12GB of space for MP3's, i'm under the impression that you can connect this to a raido with a 3.5mm audio jack, similar to what you'd connect an ipod with. I've asked my citroen dealer about connecting an auxilary input to the radio and they didn't have a clue what i was talking about, they emailed France, but i've heard nothing since. So my question is this: Is it possible to connect 3.5mm jack to the back of the standard radio? If yes, do i need to purchase anything in advance of doing this? Do the garage need to do anything, i read something about them needing to activate the aux input. Has anyone got any tips on performing this procedure? Thanks in advance.