Lana Z Port Huron , MI July 03, 2016 Appliance: General Electric Refrigerator TBX18MASGRAD Ge Refrigerator Tbx18masgrad: Defrost not working no cold air getting to fresh food. How to replace Defrost Heater Kit (Refrigerator). Replace defrost timer and defrost heater kit. repair only took about 30 min. but took almost all day to defrost fridge before starting repair, used hair drier to defrost freezer area. 3 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 2+ hours