Wine cooler shows E3 and the compressor or thermoelectric module does not run correctly; temperature fluctuates widely.

Unplug the unit before servicing. Internal components can be live even if the compressor is not running.

Steps:

• Identify sensor location: On compressor-based Koolatron wine coolers, the evaporator sensor is usually clipped to the evaporator coil behind the interior rear panel. On thermoelectric models, it may be attached near the cold-side heat sink.
• Remove interior panel: Take out shelves, then remove the interior rear panel (usually held by screws or clips). Be gentle to avoid cracking the liner.
• Inspect the sensor: Look for a small probe or bullet-shaped sensor attached to the coil or heat sink with a clip or tape. Check for corrosion, broken wires, or dislodged mounting.
• Check wiring path: Follow the sensor wire to where it exits the cabinet and ensure it is not cut or pinched.
• Test with multimeter: Measure resistance at room temperature. If the reading is infinite (open) or extremely low (short), the sensor is bad.
• Replace sensor: Install a new Koolatron evaporator temperature sensor. Clip it firmly to the coil or heat sink in the same position to ensure accurate readings.
• Reassemble and test: Reinstall the interior panel, plug in the unit, and verify that E3 clears and cooling resumes.