Description
Sunlight intensity sensor suitable for Peugeot 307, 308, 406, 3008 and 5008 and Citroën C4, C4 B7.
This OEM-style sunlight (solar) sensor (part numbers 9833418780, 6445NH) is designed to provide accurate solar load information to the automatic climate control system in Citroën and Peugeot vehicles. By measuring the intensity and angle of incoming sunlight, the sensor allows the HVAC system to apply sun load compensation — adjusting blower speed and air distribution to maintain cabin comfort and reduce unnecessary compressor runtime.
Key Features
- Direct replacement for factory sun sensor on compatible Citroën and Peugeot models.
- Measures solar radiation intensity to support automatic climate control adjustments.
- Compact, plug-and-play design in most installations; retains original mounting orientation and connector.
- Includes original product references 9833418780 and 6445NH for easy lookup.
Application
Installation Recommendations
- Switch ignition off before starting. For safety, if required by the vehicle repair manual, disconnect the negative battery terminal.
- Gain access to the sensor on the dashboard (typically near the base of the windshield or inside the top dashboard trim). Use plastic trim tools to avoid marking interior panels.
- Carefully remove the trim piece securing the sensor. Unplug the electrical connector by releasing the locking tab — do not pull on the wiring.
- Remove the old sensor from its bracket or housing and fit the replacement in the same orientation. Do not touch the sensor’s sensing surface with oily fingers.
- Reconnect the electrical connector, reassemble trim, reconnect the battery if disconnected, and start the vehicle to verify proper HVAC response. Test the automatic climate control in sun load conditions to confirm correct operation.
Why It Fails
- Exposure to prolonged UV and thermal cycling can degrade the sensor’s optics or electronics, causing drift or intermittent readings.
- Moisture ingress or condensation, often due to cracked housings or damaged seals, leads to malfunction.
- Connector corrosion or wiring damage (chafing, rodent damage) causes intermittent faults or complete loss of signal.
- Contamination (dust, adhesives from dashboard repairs, or tinted film applied to the windshield) can alter measured values and confuse automatic climate control logic.
- Mechanical impact during dashboard repairs or improper reassembly can misalign the sensor or damage the mounting clips.
Maintenance And Diagnostics
There is no fixed replacement interval for the sunlight sensor; it is usually replaced when climate control behavior becomes erratic (e.g., incorrect blower speeds, sudden temperature swings, or related fault codes). Diagnostics typically include visual inspection of the sensor and connector, checking for fault codes in the HVAC module, and verifying sensor voltage/signals with a multimeter or diagnostic tool.
Technical Information
- Manufacturer: Stellantis (Citroën / Peugeot)
- Model: Compatible with Peugeot 307, 308, 406, 3008, 5008; Citroën C4, C4 B7
- Product Codes: 9833418780, 6445NH
- Other Numbers: 6445NH | 9833418780
Additional Notes
When replacing the sensor, preserve the original orientation and mounting height relative to the windshield — incorrect positioning can produce inaccurate sun load readings. If replacement does not resolve HVAC issues, further diagnosis of the climate control unit and related sensors (ambient temperature, interior temperature) is recommended.
