Every ice maker begins with the supply line. Water comes from a shutoff valve, often under the kitchen sink or in a recessed box behind the refrigerator, through copper, braided or plastic tubing to the water inlet valve at the back of the cabinet. On most refrigerators it then passes through a filter before reaching the ice maker fill tube. A partly closed or clogged shutoff, a kinked line behind a refrigerator pushed back too far, or an overdue filter all cut flow. The inlet valve itself is a solenoid with a small screen at its inlet; the coil can fail open, and the valve seat can wear so it drips or sticks.
The classic in-freezer ice maker sits in an upper corner of the freezer. When the mold is cold enough, the control opens the inlet valve for a timed fill, the water freezes, a heater loosens the cubes, and a motor turns ejector arms that push them into the bin. Some newer designs twist a flexible tray instead. A wire shutoff arm or an optical sensor stops production when the bin is full. Typical failures include a motor or module that stops mid-cycle, a thermostat or thermistor that never signals a harvest, a heater that fails so cubes stay stuck, and a fill tube that freezes shut so no water arrives.
In-door ice makers, found on most French-door models and some side-by-sides, are more complicated. The ice maker sits in an insulated compartment on the fresh-food door, where the surrounding air is well above freezing. Most designs duct cold air from the freezer section through channels in the cabinet, and a fan pushes it through the compartment. If the duct ices up, the fan fails or the compartment seal leaks, production slows and cubes fuse into clumps. The same compartment houses the bucket and auger, and a stuck auger, a jammed crusher or a chute flap that no longer closes can stop dispensing even while ice is being made.
Dispensing is its own system. A paddle or button closes a switch, the control runs the auger motor to push ice forward, a solenoid or small motor opens a flap in the chute, and the crushed setting routes cubes through a set of blades. Small heaters keep condensation from freezing the flap shut. Water quality runs through all of it. Minerals collect on the inlet valve screen, inside the fill tube and in the filter; air in the line after a filter change causes sputtering; and a filter that is too restrictive or a poor fit can drop pressure below what the valve needs to fill the mold, leaving small or hollow cubes.
