I just installed a sony 7710 stereo, but I am getting no sound from the CD...

The tuner works fine and gets sound, but when I put a CD in, the screen plays the cd info and has time scrolling, but there is no sound?

Did I miss a wire somewhere? Only thing I can see on the plug is the car end has a green/white wire that I have nothing connecting to. The adapter has a brown wire there, but no label for it on the bag.

HELP!! Called sony and 45minutes got me "go to crutchfield.com" even though I didn't get it from there.

Chris