I have got my self a Sony CDX-GT230 CD player for my Citroen C3 LX (03 reg). I installed it but the volume controls on the steering wheel does not work, but after 30 mins the central locking failed, it wouldn't unlock the doors. I put the orginal original radio cassette player back in and the central locking works fine. What extra cables do I need to buy to fix this problem? TIA.

Jason, September 2009