Refrigerators have come a long ways in the last few years, there are water valves on the back of some refrigerators that are called smart valves these valve are bar none cutting edge technology in the appliance industry.
If your reading this you more than likely have no water to the door of your refrigerator or no ice production, a refrigerators valve will cause both of these issue. On most water valves there are two solenoids if you have water at the door and an ice maker there will be two water solenoids on the valve, the water valve must be replaced as an assembly.
Testing your refrigerators water valve with a volt meter is simple, a live voltage test will be needed to diagnose your water valve. If you are unfamiliar with a volt meter you can purchase one and get acquainted relativity quickly there is a lot of information on the web that pertains to basic electrical skills and ohm volt meter reading.
One of two ways to test the voltage at the water valve, you can wait behind the refrigerator until the ice maker calls for water or you can manually advance the ice maker speeding up the diagnostic process.
Here is a link with picture that will assist you in advancing the ice maker
Once the ice maker is jumped or bypassed you will need to place the volt meter on the water valves wires, if voltage is present and the solinoid does not open up you have indeed found the problem, replacing the refrigerators water valve will solve this issue. FYI the fill tube can become clogged with ice preventing water from making it up the back and into the ice maker, check this first before any test is made it’s simple and done from the front of the refrigerator.