Perhaps this will help somebody. About a year ago, our relatively new Whirlpool refrigerator has a filtered water system, and both the ice maker and the dispenser suddenly stopped working. I could hear the electric water solenoid operate, but no water would come out. The water filter had been changed recently, so I was fairly confident that it wasn't the source of the problem, but removed it nonetheless.
(As an aside, the manual states that although it is recommended, the filter is not necessary for the system to operate (but considering the difference it makes in the taste of our water and ice, i wouldn't even think of not using one!) and the filter is easily removed and replaced without having to shut off the water at the wall valve.)
The system still failed to operate without the filter in place. Naturally i then checked for good water flow at the line, and it was fine. Not knowing what else to do, I called for a repair tech.
A repairman came out and disconnected all the lines, valves, etc. and could find no problem. Yet when he reinstalled everything, the water flowed normally! All he could say is there must have been a small blockage somewhere in the line that resolved itself with his disturbance of the system parts, and consequently charged us for a service call.
Fast-forward 1 year: the system suddenly stops working for the 2nd time. Again, I had changed the filter about two month previously, so routine maintenance wasn't suspect - but I removed it and emptied it out (you be amazed at the black particles that come out, after only a month or 2!), and tried the water dispenser - still nothing. Again, i disconnected the water line and verified good flow.
I reconnected the water line and reinstalled the filter (which I had emptied), and upon trying the water dispenser again I could hear water flowing into the filter - and then stopping. This told me - and I think this is a key point to check - that water was at least getting that far into the system.
Determined not to call out the repair man again, I then went online searching for a solution, and read somewhere that a user reported finding a "frozen water tank" in his refrigerator's water system (make and model not mentioned) which of course prevented his ice maker from working which he subsequently determined was caused by a blockage. Suddenly it hit me: Recently I had taken a beer from the fridge, and found it to be slightly-frozen, which was unusual (we keep both the fridge and the freezer temperature settings slightly colder than the "normal" mark.) I mentioned this to my wife, and she remembered that she, too, had removed something from the refrigerator section that was also frozen. Could it be that our problem was as simple as a frozen water line, tank, etc?
Consequently, we removed everything from the freezer, placing the contents temporarily into ice chests, and unplugged the refrigerator power cord. Thirty minutes later, I reconnected the power and - whatddya know, the water flowed! (Note: the fact that the repair technician had the power off for about half an hour is no doubt what "fixed" the problem the first time, as well; i.e., the ice blockage had time to thaw.)
I changed the thermostat setting of both the fridge and the freezer sections to a "hair" on the warm side of normal, and I fully expect that this will solve the problem.