The first type I’m going to discuses is,  where the ice maker dumps the ice into a bucket
that is located inside the freezer and usually you can remove this bucked, this bucket
holds the ice for your front dispenser, The second type is where the ice bucket is
located in the door. (( this type has many of the same principals, with the exception of
the location of the ice maker and the ice bucket and has an emitter board.))

How it works:

The ice maker uses the freezer to freeze the water in its tray and when the ice maker’s
thermal sensor detects that it is below about 14 deg. F. It goes into a cycle which turns
on the heater to release the frozen cubes and at the same time turns on the motor to
rotate the fingers that will push the cubes out and let them drop in the bucket. Before
the cycle is finished it turns off the heater and turns on the water valve (located at
bottom rear of the machine) to refill the ice maker tray with water. This is the end of the
cycle and it will repeat until a bucket of ice holds the ice maker’s fill level arm in the up
position to tell the ice maker to stop.
To clarify:
The ice maker does not freeze the water, the freezer’s cold air does.

Common Ice Maker problems

A lot of ice makers have a metal arm and if it is in the up position it is in the off position.
And you will need to pull it down.
Water supply shut off valve at your wall is not turned on.
Your freezer is not getting below 14 deg. F
Your water valve has a slow leak and has frozen the fill tube.
Your water filter is bad and is restricting water flow.
Your water valve is bad and will not let water fill the ice maker.
The ice maker itself has failed for the following reasons: The heater is bad, the motor is
bad or the thermo sensor is bad.
There are other reasons and problems you could be having with your ice maker
system. The ice maker dispenser is not covered in this section.

The second type.  Your ice bucket is in the door of the freezer.

You have an emitter board that has priority over your ice maker.  This emitter board
has a few functions, one is that if you open your freezer door it does not allow the ice
maker to dump ice, another function of the emitter board is to check the level of ice in
the bucket, and one more nice function of the emitter board is to give you error codes if
there is a malfunction.
This type of ice maker set up can have the same problems as I have described above
with one more problem, and that is an emitter board malfunction.  If the emitter board
malfunctions it won't allow power to the ice maker.