aftermarket radio

[davidamd]

ok some may have read the last thread on the oem upgrade of which i had no joy as i dont have bose.
the car is a pf 97 a8.
it had the basic radio in but i had no conectivity in the modern day. so i bought a kenwood kdc 200ub to go in its place.
not the back of my old set all the speaker pins were there so in theory the new kenwood set should use all the pins but i can only get sound through front speakers no rear.

anyone know what the reason may be out of thr many ti pick from