It is interesting how no one will touch on the number one reason why Ice makers fail. As a technical advisor for a major corporation, I see 95% of Ice making failure is inadequate door suction(seal) issues. The temperatures become unstable with warm air seeping into fresh food door if not suctioning to front of frig. When temperature sensor senses the warmer air, the controller keeps the compressor running overtime to maintain the 37 degrees in the fresh food. This will cause the freezer temp to fall below zero, which will freezer the tip of the water tube that provides the Icemaker with water. It is a fact that anytime the freezer drops below zero, the defrost cycles can no longer maintain a thawed water tube for the IM. Please keep in mind that the controller's main priority is the fresh food, since a 3 degree increase will cause rapid food spoilage.
The door suction must be maintained. Most technicians as well as "so called experts" are totally unaware that the doors need to be self closing. The doors are big suction cups. A suction cup needs pressure to stick. The doors need their own weight to press them, through use of the earth's gravity. The leveling rollers or legs need to be adjusted to provide a tilt back of the frig to enable the earth's gravity to get ahold of these doors/drawers. Suction will happen while compressor is active, due to air flow; the compressor shuts down and all suction is lost. Just as your dart fell off the mirror when you shot your dart at the mirror as a kid, so does the frig doors from the front of frig. If you tilt the frig back, your doors will be heavy to the front of the frig cabinet and will suction. Temperatures will stabilize in frig and freezer. Within 24 hours, the defrost cycles will thaw the water tube and ice production will start.
Obviously there can be other variables that can contribute to bad suction, such as a damaged door gasket. One should always be looking for the obvious.
Yes, there are other potential causes, but I find that 9 out of 10 times, if the frig doesn't even have the basic conditions needed for successful ice making, then how can you even begin to blame the problem on failed parts....that can get very expensive- Door suction issues can cause water flow issues to the dispenser as well, as the compressor overworks and brings in an extreme amount of cold air, which freezes the water tube and reservoir in back of frig behind back wall. Temps should be a perfect balance of 37 frig, 0 freezer with good door suction. With water flow and good temps, the IM should make ice. If you have perfect conditions first, and still do not have ice, then you can start looking at replacing Ice machine or inlet valve depending on situation.