Is there ice in the ice maker tray now? If yes lift the arm up and let it drop down hard and see if it dumps the ice then.
If there is no ice in it now, pour water in the tray and see if it dumps when it freezes.
If it dumps the ice but don't refill with water
Check water inlet valve
http://www.acmehowto.com/howto/appliance/refrigerator/check/inletvalve.php
A strainer before the inlet valve can also get stopped up restricting flow. |