Hi.. i am new to the mercedes era of car and recently bought a w203 year 2002 c200

on board i have the audio aps 30 command after getting a new harman becker navigation cd..i ve upgraded my 5.0 software to 6.0 eveything went fine with no problem..gives me the countries and town but once reaches town its stop here and i can find its not connected/ receiving any satellite signal...switched back to old cd..the same thing no connection

can any 1 plz help how to switch back the signals on?

thanks