Ice maker has trouble making ice cubes. When I look at the ice maker, it makes an audible clicking sound and the ice 'pushers' don't appear to push the ice cubes out of the tray. The tray seems to have a bit more water than it should, but I'm not sure what 'normal' is. Or maybe the heater element is broken. I think I can replace the ice maker myself. Could the problem be somewhere else?