Got it fixed.
The dealer was down by my boat (his boat is two slips from mine) and I explained the problem. He called his electronics guy down, and found there is a blade fuse in the back of the amp, which is mounted under the helm accessible through the cabin. Replace the fuse and 3 of the 4...
I did find the fuse for the amp located in above the batteries and changed it although it looked good. No change.
I've pulled the head unit and all the connections look good as well.
So it is either bad wiring to the amp or the amp is shot.
Where is that amp located?
Just picked up my 2005 270 Sundeck and found that there is only sound from the front speakers. (Wasn't the surveyor supposed to find that out for me?)
The four in the middle and rear aren't working.
I looked at the wiring of the unit in the head compartment and can find nothing wrong. Someone...