Alright,will try to clean the cables and will let it know how it turned out.
About the center speaker,i don't think there is one in there,i'm not using a standard radio.
Something i don't get is why i have lower soundvolume on the left and my his Passat B5.5 has the exact same problem.
It used to keep playing but the last weeks i got no audio on the left front.A little wack against my door and its fine again .
*edit ;its left hand drive btw so the drivers speaker