Freezer or combined fridge/freezer shows 4E or 4E-F; ice buildup on evaporator and poor cooling.

Safety: Disconnect power before removing panels or working near the evaporator.

• Defrost manually first: If there is heavy ice, leave the freezer unplugged with doors open for 12–24 hours (use towels to catch water). This can temporarily restore cooling and allow access.
• Access defrost sensor: Remove freezer drawers and the rear interior panel. The defrost sensor is usually clipped to the top portion of the evaporator coil, often wrapped in foil or foam.
• Inspect sensor and clip: Ensure the sensor is firmly clipped to the coil and not hanging loose. Check for cracked casing or exposed wires.
• Test sensor: At room temperature, measure resistance with a multimeter. Compare to Samsung NTC values. If open, shorted, or far off spec, replace.
• Replace sensor: Unclip the old sensor, disconnect from harness, and install the new Samsung defrost sensor in the same location and orientation. Re-wrap any insulation or foil tape.
• Reassemble and test: Refit the evaporator cover, ensuring foam seals are tight. Restore power and monitor for 4E returning. If the error persists, the main PCB or defrost circuit may be faulty and should be checked by a professional.