A flaw in the design of these units causes door insulation or seal to deteriorate over time and as a result freezes the water line inside the door by the H2O discharge area. You can order the heater kit and install it or you can try the following fix that cured it for me and cost almost nothing. I used a styrofoam crawlspace winter vent cover and affixed it to the inside of door directly behind the water/ice outlet using two-sided tape. I also removed the front assembly to the H2O/ice dispenser and stuffed a short piece of round foam insulation in the problem area. The pictures will explain it better. I am not sure what method of the two worked. You could start with the easier, crawlspace (or any styrofoam) mounted to the inside door.