Description
Interior Air Temperature Sensor For Peugeot 406 And Others. Valeo Evaporator Probe.
This used interior air temperature sensor is a direct-fit evaporator probe commonly found on Peugeot 406 and some related Citroën/Peugeot HVAC assemblies. Supplied as a Valeo-type probe, it measures the air temperature around the evaporator and provides the climate control unit with the data needed for precise cabin temperature regulation. Frequently searched by part numbers 664916Q and 6445NG, this sensor is suitable for professional workshops and DIY mechanics looking for a reliable replacement part.
Function And Application
The sensor monitors the temperature of the air in the evaporator or HVAC housing and sends this information to the climate control module. Accurate readings prevent evaporator freezing, help regulate compressor cycling and ensure the automatic climate control maintains the set cabin temperature. This item is most commonly used on Peugeot 406; it may also fit other Peugeot and Citroën models that use the same Valeo evaporator probe design. Customers often locate this part by its product codes (664916Q / 6445NG).
Common Faults And Causes
- Moisture Ingress And Corrosion: Exposure to condensate and humidity can corrode the sensing element or connector contacts, causing erratic readings.
- Connector Or Wiring Damage: Broken pins, loose terminals or damaged wiring lead to intermittent signals or total failure.
- Physical Damage: During HVAC servicing or foam/dash removal, the probe or its mounting clip can be cracked or displaced.
- Aging And Drift: Over time the sensing element can drift outside acceptable tolerance, resulting in incorrect cabin temperature regulation.
Installation Recommendations
- Safety First: Always disconnect the battery before beginning work to avoid short circuits or ECU issues.
- Access: The sensor is usually located in the evaporator housing or HVAC case behind the glovebox or lower dash. Some models require removal of trim or the glovebox for access.
- Removal: Carefully unplug the electrical connector, release any retaining clip and withdraw the probe. Avoid forcing or twisting the sensor to prevent breaking the housing.
- Fitting: Insert the new probe until fully seated and secure with the original clip or a replacement. Reconnect the electrical connector ensuring clean, dry contacts. Replace any damaged seals or foam to preserve airflow paths and prevent moisture intrusion.
- Testing: Reconnect the battery and verify climate control response and temperature readings. Typical replacements do not require coding; however, perform a functional check of the HVAC system after installation.
- Recommendation: If access is difficult or wiring/connector repair is needed, have the job performed by a trained technician.
Technical Information
- Manufacturer: Valeo
- Model: Peugeot 406 (Common Application)
- Product Codes: 664916Q, 6445NG
- Other Numbers: Not Available
Why Replace This Part
An inaccurate or failed evaporator probe causes poor climate control performance: incorrect cabin temperature, longer compressor run times, or even evaporator icing. Replacing a faulty sensor restores proper feedback to the HVAC system and improves comfort and efficiency.
