then I would guess that it has something to do with the thermistor, even though you said it checks good, with your meter. It's possible that the board is not reading the proper input from the thermistor, so I would ask you to check the resistance of the thermistor at the ice maker control, on the back. This is just to once and for all eliminate the thermistor.
The basic principal is that the unit fills, makes the cubes, the thermistor senses the change in temp, and then the unit cycles the hot gas valve, and moves the mold to fill, The hot gas valve lets the evaporator warm up so that the cubes can drop, and fill the bucket, after the cubes drop the thermistor again senses the temp change and then shuts down the hot gas valve, and the process starts all over again.
BTW There are several repair kits for these IM, I just dont know the part numbers to order to get them going again. If someone was factory authorised they maybe could find and post the service updates, and that may help shed some more light on the subject.
OK, I checked the thermistors at the back of the refrigerator. The Ice Mold thermistor reads 69.2, which equates to -2 degrees. The evaporator thermistor reads 16.6 which equates to +54 degrees.