Dehumidifier shows E3 and stops cooling; fan may continue to run.

Safety: Unplug the unit before removing the control panel or front cover.

Steps:

• Power cycle: Disconnect power for 5 minutes, then restart. If E3 returns, continue.
• Locate humidity sensor: On Mitsubishi Electric dehumidifiers, the humidity sensor is often mounted behind the front grille near the air intake or integrated into the control panel area with a small vent opening.
• Inspect sensor and wiring: Remove the front panel/control panel. Look for a small PCB or capsule labeled as RH sensor with 3–5 wires. Check for loose connectors, corrosion, or signs of moisture ingress.
• Clean gently: If the sensor is dusty, blow with dry air or use a soft brush. Do not use liquid cleaners on the sensor element.
• Check harness continuity: Ensure the harness from the humidity sensor to the main PCB is intact and firmly seated.
• Functional test: If you have access to service mode (varies by model), check if the displayed humidity changes when you breathe gently near the intake. If it does not change or E3 persists, the sensor is likely faulty.
• Replace sensor: Replace the humidity sensor assembly. If a new sensor does not resolve E3, the main control PCB is likely defective.

Tip: Mark connectors before removal to avoid mis‑wiring when reassembling.