[happysak]

water dispenser works but ice maker is not filling. Is the problem in the water valve or in whatever it is that tells the valve to open and close. By the way, what is it that tells the water valve to open or close?

[woodchuck]

The ice maker goes through it's cycle when the water is frozen. The motor turns the ejector and pushes the ice out. The motor continues to turn and triggers a switch which opens the water valve for a set amount of time to fill the tray. Test to make sure the water inlet valve works. Refrigerator Repair Guide: How to Check the Water Inlet Valve - ACME HOW TO.com

If it's ok the ice maker would be at fault. Some have replaceable parts and some you have to get another ice maker. MSD2454GR Parts List