Safety first: Disconnect power before accessing the freezer evaporator or control board.

dH indicates the defrost cycle is running longer than expected, which can overheat components.

Inspect evaporator area: Remove the freezer rear panel and check for signs of overheating, melted plastic, or deformed foam around the evaporator.
Test defrost thermostat: With the coil cold, the thermostat should be closed; as it warms above its rated temperature, it should open. If it remains closed when warm, replace it.
Check heater resistance: Test the defrost heater for proper resistance. A very low resistance or visible damage may indicate a shorted heater.
Verify thermistor placement: Ensure the evaporator thermistor is clipped in the correct location on the coil and has not fallen off or been relocated.
Control evaluation: If components test normal, the main control board may be mismanaging defrost duration and should be checked by a professional.

Display shows dH and there may be excessive frost or long defrost times.

Possible Causes