E7 error code and excessive frost buildup on back wall or around evaporator

Safety: Unplug the cooler before defrosting or accessing internal wiring. Water from melting ice can create slip and shock hazards.

Steps:

• Manual defrost: Open the door and leave the unit unplugged until all ice has melted from the back wall and evaporator. Use towels to absorb water; do not use sharp tools to chip ice.
• Access evaporator: Remove shelves and the rear interior panel to expose the evaporator coil, defrost heater, and defrost sensor.
• Inspect defrost sensor: The sensor is usually clipped to the evaporator tubing. Ensure it is firmly attached and not broken or corroded. Replace if the plastic housing is cracked or the wires are damaged.
• Check heater continuity: If you have a multimeter, disconnect the heater leads and measure resistance. An open circuit (OL) indicates a failed heater that must be replaced.
• Board/relay check: If both sensor and heater test good but E7 returns and frost builds up again, the defrost relay or control logic on the main PCB may be faulty. Replace the main control board.