Tried replacing ice maker assembly (W10873741), the main water supply valve (W10498992), dual water valve (W10238100) and freezer door switch and nothing fixed the problem. Filter is new and water supply pressure is more than adequate. Was able to return all with refund, minus restocking fees and shipping so no biggee. In the end, I discovered severed wire(s) at the lower freezer door hinge area that over time were cut due to opening/closing freezer door. Was able to reconnect severed wires using solder, but I expect that some time in the future the problem will occur again. At least then, I will know where to look first and not have to hunt and peck my way through the repair. I am now very intimate with the workings of my ice maker system and hope this helps others in similar situation.