Samsung Refrigerator Defrost Thermostat Replacement Guide — What This Part Does
The defrost thermostat is a temperature-operated switch mounted on or near the evaporator coil in the freezer section. It terminates the defrost cycle by opening when the coil warms up to the correct temperature, preventing the heater from overheating or wasting energy. If the bi-metal contacts fail and the thermostat stays open when cold or fails to open when warm, the defrost control logic cannot function correctly and the evaporator will ice over, blocking airflow and reducing cooling performance.
Samsung calls this part the freezer defrost high-limit thermostat or bi-metal defrost thermostat. It fails when the internal bi-metal contacts wear out and no longer change state at the correct temperature. Wiring damage, loose connectors at the evaporator harness, and heavy frost buildup from a failed defrost heater can also make the thermostat appear defective, so technicians test both the thermostat and heater before replacing parts.
Signs It Needs Replacing
- Heavy frost or ice buildup on the evaporator coil Thick frost covering the coil in the freezer compartment means the defrost cycle is not terminating correctly.
- Freezer running but fresh-food section warm Blocked airflow from iced coils prevents cold air from reaching the refrigerator compartment.
- Continuous fan noise or reduced airflow The evaporator fan struggles to move air through ice-blocked coils, creating unusual sound or weak airflow from the vents.
- Defrost heater stays on too long or never activates A stuck-open thermostat prevents the heater from cycling, or a stuck-closed thermostat lets the heater run continuously.
- Water pooling under crisper drawers or on floor Excess frost melts during manual defrost or defrost overshoot and overflows the drain pan or drain tube.
- Thermostat fails continuity test when cold Testing with a multimeter on the ohms setting shows no continuity through the thermostat at normal freezer temperature.
How to Replace It
- Unplug the refrigerator from the wall outlet before any disassembly or testing.
- Remove all freezer baskets, drawers, and drawer rails to access the rear evaporator cover panel.
- Unscrew and lift off the evaporator cover panel to expose the evaporator coil and defrost components behind it.
- Locate the defrost thermostat clipped or zip-tied to the evaporator coil tubing, usually near the top or center of the coil assembly.
- Disconnect the wire harness plug from the thermostat leads, or cut the wires if factory-crimped, noting wire colors and positions for reconnection.
- Test the old thermostat with a multimeter set to continuity (Ω) while cold to confirm it is open or stuck, then replace if it does not change state with temperature.
- Clip or zip-tie the new thermostat to the same mounting location on the evaporator coil tubing, positioning the sensing bulb flat against the tube.
- Reconnect the harness plug or splice the wires with heat-shrink connectors and secure the wire bundle with new zip ties as in the original routing.
- Reinstall the evaporator cover panel, freezer rails, and drawers, then plug in the refrigerator and verify normal defrost cycling and cooling over 24 hours.
The Part You Need
| Part | Notes |
|---|---|
| Samsung defrost thermostat (bi-metal / freezer defrost high-limit thermostat) | Amazon | Common part number DA47-00243 fits many models. Find your exact part number on the model and serial plate inside the fresh-food compartment or on the left sidewall, then cross-reference by full model number at Samsung Parts or an appliance parts supplier. |
Related Error Codes
If this part is failing you may also see one of these codes:
- Samsung Refrigerator 1E error code
- Samsung Refrigerator 21E error code
- Samsung Refrigerator 22E error code
- Samsung Refrigerator 25E error code
- Samsung Refrigerator 2E error code
- Samsung Refrigerator 33E error code
- Samsung Refrigerator 39E error code
- Samsung Refrigerator 4E error code
- Samsung Refrigerator 5E error code
- Samsung Refrigerator 88 error code
When to Call a Pro
Call a technician if you are not comfortable working behind live evaporator coil assemblies, if the defrost heater or main control board also needs replacement during the same repair, or if the refrigerator uses a sealed refrigerant system that was opened or damaged during disassembly. Technicians have the tools to test the entire defrost circuit (thermostat, heater, timer, and control board) in one visit and can source the correct revision of Samsung-specific thermostats that vary by coil design and refrigerant type.