I've got a grundig ms201a radio fitted to my skoda, which works ok, after learning that a cd changer could be used with this radio I bought a used cd changer off eBay, basically a standard one that all vag group cars have fitted part 1Z0035111. But after fitting it, when the cd button on the radio is pressed "EXPERT" flashes up followed by "SAFE" permanently on and nothing happens, if cd is pressed again it goes back to the radio mode again. I will also point out the lights on the changer work and CDs can be loaded. So is a code needed for it, or will it not work with my radio. Thanks