There are too many questions on this guestion to address each one. If you post your question as a new question you’ll have an answer for your individual problem. Here are some fix’s for several situations.
'''Ice maker quit after replacing water filter.'''
Flush the air out of the water lines by letting the water dispenser on the door run about a gallon or more water through it. It’s boring, but air can take as long as10-15 min to get flushed out. I’ve seen many brand new filters fail.
'''Is the ice maker ON?'''
This is a very common problem. Children might play with the display and turn it off. Some have a on/off switch on the I/M, on the display, on the wall in freezer etc.
'''It makes one tray and stops when reset button is pushed.'''
Pushing the reset button on the I/M bypasses the heater thermostat. It will dump the ice, fill than freeze but never drop the new ice. This is due to a bad heater thermostat. Most technicians replace the I/M instead of replacing the tstat. Replacing the tstat is time consuming and the labor cost is high. It’s more cost efficient to have a new I/M. You can replace the tstat if you have time and patience.
I'''f you hear gears turning but don’t see anything moving.'''
The gears that turn the fingers that push the ice out are stripped. This can happen due to sediment in the water building up on the ice tray and making it hard for the ice to release from the tray. You need a new I/M.
'''The cutoff arm doesn’t move.'''
The arm slips into a slot on the I/M head. Be sure it’s secure in the slot.
'''DIRTY CONDENSER COILS cause Ice production to slow down. Dirty coils will cause major issues.'''
The first symptom of dirty coils is slow ice production. This is due to a rise in temperature. I/M won’t advance if the temperature is above 9*F. Dirty coils restrict the air flow needed to cool the compressor and to remove the heat from the unit. The refrigerant lines are copper and heat will cause them to erode. The compressor will run hot and the next thing that happens is a no cool situation. A sealed system issue is expensive. Very expensive. Most failed compressors are due to dirty coils. You need to clean the coils at least once a year. If you have pets, clean more often.
I hope this helps you determine the problem. If not, repost your problem as a NEW question and include the model number. Thanks!