Mike C Lodi , NJ April 04, 2021 Appliance: Whirlpool Refrigerator GR9FHMXPB01 Whirlpool Refrigerator Gr9fhmxpb01: Leaking. How to replace Defrost Heater. Replaced thermostat and defrost heater element in freezer. Do-It-Yourself Rating: Repair Time Estimate: 1-2 hours