A refrigerator ice maker that freezes up can be caused by a frozen ice maker fill tube, faulty water inlet valve, too low freezer temperature setting, or a water filter that needs replacing.
First, locate the water supply to your ice maker and turn off the water supply via the shut off valve. You may want to have a bucket and towels on hand for any extra remaining water in the water supply line.
Fill Tube and Water Supply Line Frozen
The fill tube and water supply line supplies water to your ice maker. The fill tube can be a separate part that connects to the water supply line and it enters from the back of your freezer and into your icemaker. You may need to remove your icemaker to see this tube and to check if it is frozen.
If the fill tube is frozen, you will need to thaw it out using hot water pored over the tube using a turkey baster, or else remove this part from your refrigerator and thaw it out in the sink. You can remove this part from behind your fridge by unscrewing a few screws and detaching the water supply line. Thaw in your sink and reattach.
Some methods suggest using a hairdryer to thaw out this part. Be careful when using this method as dripping water and electricity could lead to a possible electric shock. Also, exposure to long periods of heat could damage the fill tube part.
Replace the Water Filter
If you have a refrigerator water filter, check to see if it needs replacing or consider replacing it.
Reset the Freezer Temperature
Check the temperature setting on your freezer as it might be set too low. You may want to bump it up a degree or two.
Test the Water Inlet Valve
You may want to also test the water inlet valve. The water inlet valve controls the flow of water into the ice maker and is located in the rear of the refrigerator behind the back access panel. Sometimes this part can go bad and overfill the ice cube tray when it is not needed.
The water inlet valve also has a screen filter that can become clogged with sediment and minerals from hard water over time. Remove the water inlet vale from the refrigerator and use a flat head screw driver to remove the sediment screen from the part. Clean the filter screen using soap and warm water and replace. Reassemble all parts and test your ice maker.