Tower Speaker Not Working???

Hey guys,
I have a 2002 X-9 with the Clarion audio system and M-60 tower speakers. My problem is only one is working. All the audio setup is factory as far as I know and I've tried hooking another speaker up to the wires and still get nothing. Any thoughts?
The wiring is running out from the stereo into one of three amps (boat, sub, tower) and is set up to have tower on rear balance with boat front.
I've also noticed when I shift balance to Left there is no audio at all??? Is that a part of having to shift things for the Front/Rear set-up?

if you tried another speaker and there's nothing, then it's not the speaker. you could have a bad RCA between the HU and the tower speaker amp, or you could have a bad wire from the amp to the tower speaker. try switching speaker wires at the amp and see if your R speaker plays. if it does, then chances are it's the L speaker wire to your L tower speaker. if it doesn't your amp isn't sending out anything so move on to the RCA's from HU to amp and check those. make sense? make sure all the RCA connections are good, clean and solid. oh, also check your fuses on the amp. good luck!