2 answers

  1. Most icemakers have a bail arm that can be lifted to turn the icemaker off and some icemakers have an on/off switch. In either case, if the arm is raised or the switch turned off and the icemaker continues to make ice, the best solution will be to turn the water supply valve off, until the icemaker or boards (depending on the model), can be replaced. This will also shut the water off to the water dispenser, if this fridge has a dispenser.

  2. If raising the bail lever doesnt make it stop,try unplugging the icemaker's electrical connector from the back wall of the freezer.If that doesn't make it stop (tho i cant imagine why it wouldn't,but who knows without being able to see it) shut the water off at the house plumbing.If you do that it will still buzz and rotate the mechanism,but if it doesnt have any water it can't possibly make any ice.