Kenmore/Whirlpool Frig Ice Maker Problem

The frig is less than two years old. It is a side-by-side model. The ice maker dispenses cubes into a container in the freezer door. There is a photocell circuit that detects when the ice container in the door is full. There is an ice maker on/off switch panel in the freezer compartment that also contains the photodetector emitter.
The ice maker stopped working. I have been trying to diagnose the problem. Water inlet valve is fine. The ice maker itself seems to cycle fine and make cubes - when there is voltage to the ice maker from the refrigerator.
The trouble is that sometimes the 115V line to the ice maker has voltage on it, and mostly it doesn't. I cannot for the life of me understand what the trouble is.
When I put a voltmeter on the input wires to the ice maker, there is normally no voltage present. What can interrupt the supply voltage? There is the ice maker on/off switch in the freezer compartment. If I switch this back and forth it seems to make no difference - no voltage to the ice maker. I removed the switch panel from the side of the freezer compartment to see what it looks like, and there is a small circuit board attached to the back of the switch panel, and a four wire connector. The circuit board undoubtedly processes signals from the ice bin full emitter and detector, as well as the setting of the on/off switch. I have no idea how to diagnose this circuit board.
Can somebody help me out? I am thinking that there must be some sort of repair manual that exists someplace, or some type of diagnostic help on the internet, but all I can find is diagnostics for the ice maker itself.
I am stuck.
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