Freezer is too cold; items near the back are rock-hard and frost-covered even on a moderate setting.

Safety: Unplug the freezer before accessing the thermostat or control board.

Steps:

• Verify setting: Ensure the temperature control is not set to maximum cold or fast-freeze mode.
• Test mechanical thermostat: On chest freezers with a dial, remove the control knob and panel to access the thermostat. Disconnect wires and test continuity while turning the dial. The contacts should open at warmer settings. If always closed, replace the thermostat.
• Check sensor on electronic models: Inspect the cabinet sensor for proper mounting and damage. Replace if out of spec.
• Control board: If the thermostat/sensor is good but the compressor never cycles off, the control board relay may be stuck and should be replaced.