Works fine but then fan shuts off in freezer it starts dipping. comes back on in a while and starts working.
You say the unit is not cooling but then you say that the unit "Works fine" so I am not sure what your problem is.
The unit shutting off is normal when it goes into a defrost cycle.
The ice on the evaporator coils then melts and the water should drain into the drip tray under the unit.