Dehumidifier shows E3 and compressor does not start

Safety: Disconnect the appliance from mains power before inspection.

• Locate humidity sensor: On many AEG dehumidifiers the humidity sensor is mounted behind the front grille near the air intake or integrated into the control panel area with a small vented housing.
• Visual inspection: Check for dust buildup, moisture damage, or corrosion on the sensor and its connector. Clean gently with a dry, soft brush or compressed air. Do not use water or aggressive cleaners.
• Check wiring: Trace the cable from the humidity sensor to the main PCB. Ensure it is not pinched by the cabinet and that the plug is fully seated.
• Functional test: If you have access to service data, compare sensor output voltage or resistance at different humidity levels. If not, temporarily disconnect the sensor and see if the error changes to a different code (refer to service manual). Persistent E3 usually indicates a bad sensor.
• Replace humidity sensor: Install a new humidity sensor assembly specified for your AEG model. Mount it in the same location and orientation to ensure accurate readings.
• PCB replacement: If a known-good sensor does not clear E3, the main control PCB may be defective and should be evaluated by a professional.