Derik P Mountain View , CA December 14, 2025 Appliance: Bosch Bottom-Mount Refrigerator B21CL80SNS/02 Bosch Bottom-Mount Refrigerator B21cl80sns/02: The refrigerator section is freezing. How to replace Defrost Heater. Replaced the defrost heater. Do-It-Yourself Rating: Repair Time Estimate: 1-2 hours