When I bought my GTi it came with the RCD300 which provided me with an MDI (I believe) input, located in drivers glovebox, installed by VW. Press CD twice, connect iPod and hey presto!
I decided to upgrade to the RCD510, and went about removing the old head unit, replacing it with the RCD510 I Had bought. Full use of radio but now my MDI iPod connector won't connect/play my iPod.
Anyone have any ideas why? Could it be to do with input pins being different between heady its?? VW quoted me £300 to have an AUX I put installed