An ice maker is actually a small appliance that resides within your freezer. It's usually independent of the other refrigerator systems and works together with a water-inlet valve in the operation cycle.
First, the ice maker signals the water-fill valve to open and flow into the ice maker tray the amount of water specified by the internal motor and switch.
When the water tray thermostat senses that the tray has reached a certain temperature, it signals the ice maker to begin ejecting the cubes, as follows.
When the wire goes all the way back down, the ice maker refills with water and repeats the process.