When a refrigerator's ice maker stops making ice, the problem is typically centered in the water fill tubes, the water inlet valve or the water filter. Troubleshooting your own refrigerator allows you to know what parts you need to fix the problem.
Check the water fill tubes
Check the ice maker to see if it has any ice cubes. If it does not, the ice maker's water fill tubes may be frozen. Inspect the fill tubes for ice build-up. If there is none, check to see if there are any foreign objects in the fill tubes. Remove them, and replace the outlet tubing leading from the fill valve if necessary.
Check the water inlet valve
Shut down the water at the main valve before disconnecting the water inlet tubing. Check the filter screen to see if it is clogged with debris. Clean the screen if needed, and replace it if necessary. Clean the water inlet valve of any dirt. Low water pressure can also cause the water inlet valve to shut off. Unplug the refrigerator before making any attempt to replace the valve.
Test the heat release ice maker
Remove the cover on the heat release ice maker. Insert an insulated 14-gauge solid jumper wire into the test points, which should be labeled "T" and "H." Once the jumper wire is inserted for 5 to 10 seconds, the motor should start, and the ice-making cycle should commence.