Note: Always make sure your filter is current if you have one. Not doing so will cause water to not despence properly
Pull the machine out and remove the lower back cover. Locate the water valve. With the water turned on and connected remove the 5/16" water line (the bigger one) and then have someone else press the water in the door. If the cylinoid is operating correctly it should spray water out.If so, you just verified that the valve and electrical portions are working properly and either the filter is bad or the resevoir, , located inside the lower refrigerator side is frozen. If no water comes out but the valve vibrates, then the valve is bad. If no water and no vibration, continue reading.With the machine plugged in but the wires that go to the valve for the dispenser off take a volt meter and place a lead to each wire and have someone press the panel in the door as if getting water. The reading should go from 0 to around 115-120 a/c.If your not getting electricity down there at anytime than thje door switch is bad.
Testing the ice maker:
As far as the smaller line (1/4") you have to manually advance the ice maker and wait for it to call for water with the 1/4" line disconnected from the valve. You can do this by getting a jumper wire, removing the cover of icemaker, which you jsut grab and pull off, and using the jumper wire insert one end of the wire into the cirle marked m and the other in the cicle marked n. Leave there until you hear a click and sometimes see a little spark behind the modular head wheel. Also if you see ice in the maker that hasn't dumper and the teeth of the icemaker are facing any direction other than two o clock position, the icemaker is bad. Also check the fill tube to be sure the no ice is blocking water from coming in.
If you need further help, I’m available over the phone at https://www.6ya.com/expert/jason_4570d45317834dd3