S80 T6 speakers
 

I recently purchased a 2000 T6. I believe it has the premium sound package with the dolby system. However i can only get the large speaker in the center of the dash to work. I dont know if i'm not hitting the right buttons or what. The fader knob doesn't make anything happen. Could it be a fuse problem? Or are they all connected by a single harness that could cause them all to go out? Thanks for the help.