How to Fix / Troubleshooting

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

Steps to resolve E3:

Power cycle: Disconnect power for 5 minutes, then reconnect. If E3 returns, continue.
Access the control panel: Remove the front bezel or top cover (depending on model) to expose the display/control board. The humidity sensor is often a small module or board connected by a 2–4 wire harness near the keypad.
Inspect the sensor and harness: Check for moisture, dust buildup, or corrosion on the sensor and connector. Clean gently with dry compressed air; do not use liquid cleaners.
Reseat connectors: Unplug the humidity sensor connector from the main/control board and plug it back in firmly.
Check for physical damage: If the sensor casing is cracked or wires are broken, replace the Keystone humidity sensor assembly.
Test operation: Reassemble, plug in, and test. If E3 persists with a new sensor, the main control board is likely defective and may need replacement.

Dehumidifier shows E3 and will not run the compressor; fan may operate intermittently.

Possible Causes