Thomas S Sandpoint , ID August 18, 2023 Appliance: Whirlpool Freezer WZF79R18DM00 Whirlpool Freezer Wzf79r18dm00: Upright freezer would not hold temperature and iced up. How to replace Thermistor. Replaced thermistors and freezer then went to -22 but ran continuously. Replaced the controller and freezer now running properly. 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes