radio no sound

I've been looking at your comments on the L322 Radio mute and have the same problem. First the sat nav dissapeared from the srceen ,then the screen went blue and now there is no sound from the radio. After reading the forum I checked the Sat nat and found it had water damage to it.I then checked the amplifier plugs in the boot and found it too had moisture on the plugs but cleaning them did not help. As a new unit it is upwards of £800 someone tolld me a BMW part no 65126952630 will do at £258+vat. Its an 2002 car-Any help?