Shower in 96 SKi Nautique not working

I have a 96' ski Nautique with PCM GT-40, The previous owner had a shower installed, but it does not work, more specfically water does not come out the shower nozzle. There is no noise of a pump running or water running to the nozzle.. I tried all the ACCY buttons, flipped the switch on off several times and nothing.
-The battery is good (brand new and runs the rest of the boat fine)
-I followed the water lines from the engine to the shower and checked all the connections
-I followed the yellow/black wires from the shower installation location all the way to the battery and they all seem to be connected. (The wires do go to what looks like a starter? on the port side of the motor toward the stern and then continue?)
- The impeller is fine and sending water all through the engine.
Ignore the white duct tape, I am replacing with zip ties.....
Ideas on what else to check?

The starter looking thing is the pump for the shower.
Like Pete said check for power at the pump until then we cant help you.

Understand that the pump is an on demand pump. In layman's terms the switch is always on and there is a pressure switch inside when you open the shower end the pump turns on when you close the shower end the pump turns off.
Also the motor needs to be running to supply water pressure to the pump.

Something is not adding up, is it a separate switch or wired to one of the dash ACCY switches? On/Off is all the pump needs.

2tall,   From your description, it might be good to get a little help from someone who is electrically savvy.   Do you have a multi-meter or a test light?      You can test the pump (dry is ok for these) by running a wire from the battery negative to the ground wire at the pump, and a 12v wire to the hot side of the pump.    If the pump is in operating condition, the motor will spin when you connect the two jumper wires.   
    The on demand switch as described by Gun driver is in the pump itself.    The way it works is when the water in the pump gets to a certain pressure, the switch turns the motor off.    you still need to use the breaker switch at the dash to turn the system on or off.    

-when the accy circuit breaker is in the on position (dash)
     - you should have ~12v DC when you put your meter on the two wires that feed the pump ( (1) ground, (1) 12v hot.)
   -   if you can't get 12v at the pump, there is something wrong with the wiring between the battery and the pump
   - if you try to bypass all this stuff to make the motor run (described above) you can see if you have multiple issues or just a wiring issue.
   -   if everything is working right, you should get the pump motor to turn, until you shut the valve at the end of the hose(shower head).   the pump will run until water pressure is built up in the line, and then it will shut off when it reaches its preset pressure.   

I have a multi-meter. I used it and put one end on each wire (one on yellow/one on black) and the pump ran. So it seemed like it completed the circuit? After I hooked up the toggle switch, when I click the switch on, the pump runs, but the boat won't turn over.

I may just scrap the whole thing and start over with something different. Since the plastic is so old on the dial connections (and under the engine cover getting heated up, then cooled down a lot) one of the connections broke while I was installing the toggle switch. I don't want to fork out $375 for a new shower. I might just call it quits on this shower and maybe look for another alternative.

So I am now thinking about what else I could do for a shower that would be inexpensive? I already have the peacock for the hot water on the engine...I am thinking about maybe just changing that to a shut off/on valve and just running hot water only through the existing hot tube back to the shower head.

Any thoughts are appreciated, and thanks everyone for your great input.

JD,
As Kris mentioned, I too feel it would be a good idea to find a friend who can help out with the electrics. Something is amiss with the wiring. You need to think about the boat not starting with your wiring job. There could be a serious problem. Don't run away from the problem and try to "back yard" it!!!