Display shows H3 and freezer may not defrost properly or may overcool.

Safety First: Unplug the freezer before removing the evaporator cover or working near the evaporator coil.

H3 indicates the control is not receiving a valid signal from the evaporator temperature sensor.

• Step 1 – Access evaporator area: Remove baskets and shelves. Take off the rear interior panel (evaporator cover) by removing screws and gently pulling it forward.
• Step 2 – Locate the evaporator thermistor: It is usually clipped to the evaporator tubing or mounted on the evaporator cover with two wires leading to a connector.
• Step 3 – Inspect for ice and damage: Check for heavy frost buildup around the sensor and wiring. Look for broken insulation, corrosion, or a loose connector.
• Step 4 – Test thermistor: Disconnect the thermistor and measure resistance. Compare to the temperature/resistance chart (often ~10kΩ at 77°F, higher at colder temps). Replace if open, shorted, or out of spec.
• Step 5 – Check harness: Follow the harness from the evaporator to the control board. With power off, verify continuity and repair any damaged sections.
• Step 6 – Replace control board: If the thermistor and wiring are good but H3 persists, replace the electronic control board.

After repair, reassemble the evaporator cover carefully to avoid air leaks that can cause frost issues.