The 4 most common part(s) or condition(s) which cause the symptom Refrigerator ice maker not working are listed below starting with the most likely. Check or test each item and watch any available videos.
If the ice maker is not working check the temperature of the freezer. If the freezer temperature is above 10 degrees F. (-12C) the ice maker will not work properly. It functions best when the freezer temperature is set between 0 and five degrees F. (-18 to -15C). If the freezer temp is too high make sure the condenser coil is clean and the condenser fan is working to cool the condenser and compressor. Check the evaporator coil for frost. If too much frost is built up the air can't circulate thru the coil and you will need to check the defrost components for a failure.
RepairClinic Item # 1016069
If the ice maker is not working it could be that the ice maker assembly itself is defective. The freezer temp should be between 0-5 degrees for the ice maker to cycle properly. There are several components in the control module of the ice maker that can fail and most are not sold separately. Also, ice makers have a relatively short lifespan and so it might not be worth fixing. If other, simpler parts like the water inlet valve or shut off arm have been ruled out, and the only thing left is the ice maker itself, replace it as a unit.
If the ice maker is not working the water pressure in the house might be too low. The water inlet valve which supplies water to the ice maker is designed to work with a minimum of 20 psi of water pressure.