Americo S Mahopac , NY August 27, 2019 Appliance: Model HTM181BPMRSA Coils in freezer freezing up First I replaced defrost timer but didn’t work, then I replaced the defrost thermostat and it worked, that was the problem, now I have an extra defrost timer, it only took me 30 minutes for both. 7 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes