Hia and wl;ecome to FixYa, I am Kelly.
We really need a make and model number to provide you with specific unit applicable information but.... in general, here goes:
1. Ice makers must have a freezer temp below 16 Deg F. If there is an airflow problem in the freezer caused by a fan or ice build up the ice maker will no longer make ice.
2. The ice maker has a thermostat that controls the harvest and fill cycle. If the thermostat fails it will stop making ice.
3. There is a water valve in the back of the unit that has TWO electric solenoids on it. One for water in door and one for ice. If a solenoid fails it will stop providing water to the applicable function. I.e water in door or ice. You can briefly remove the fiberboard back cover to gain access to the water valve. Then switch the installed terminal connection between solenoids. Left to right or front to back depending on how it is mounted. Then try the water in door. If water flows to the ice maker when water in door switch is actuated then the solenoid for making ice is good and the probem is with the icemaker. (Reconect wires in original positions.)
Note that anytime you remove power from the unit you must wait 10 - 15 mintues before re-applying power so the coolant system can stabilze. Other wise the compressor will not start.
Here is a web link that will help most people troubleshoot ice maker problems:
The link above is pretty good.
There is a 48 page job aid also for whirlpool in door ice that is also a big help:
This should help you find out why it is not making ice.
Thanks for choosing FixYa,