Description
Heating Servo Motor by Magneti Marelli For Citroën And Peugeot Vehicles. For Manual Climate Control.
High-quality replacement heating servo motor (blend door actuator) designed for Citroën and Peugeot vehicles with mechanical/manual climate control. This unit from Magneti Marelli restores precise control of airflow and temperature mix in HVAC systems, eliminating common symptoms such as stuck flaps, incorrect cabin temperature and grinding noises. Frequently searched under part numbers A21900100 and 6447KF, this servo is a practical choice for professional workshops and DIY car owners who need a reliable, direct-fit solution for affected Stellantis Group models.
Technical Information
- Manufacturer: Magneti Marelli
- Model: Citroën, Peugeot (e.g., Peugeot 307 II)
- Product Codes: A21900100, 6447KF
- Other Numbers: NFP
Function
The servo motor drives the HVAC blend/air distribution flaps in vehicles with manual climate control. It converts electrical pulses into mechanical movement to position heater/ventilation flaps, regulating air flow path and cabin temperature. Smooth and accurate flap movement is essential for passenger comfort and proper operation of the heating system.
Fitment And Replacement
Replacement is typically performed from under the dashboard or from the glovebox area depending on the vehicle model. General steps: disconnect battery, remove the necessary trim or glovebox to access the HVAC housing, unplug the electrical connector, remove the fasteners securing the servo, replace the unit and reassemble. After installation, verify correct flap movement across all control settings and listen for abnormal noise. Use caution with fragile plastic gears and linkages when fitting the new servo.
Why The Part Fails
Common failure modes include worn or broken plastic gears, motor burnout from overload or age, and contamination or moisture ingress that impedes movement. Symptoms of a failing servo are audible grinding or clicking, intermittent or no flap movement, and inability to change cabin temperature distribution. Failures are more common on higher-mileage cars and in environments with prolonged humidity exposure.
Installation Recommendations
- Disconnect The Battery Before Any Work And Follow Manufacturer Procedures To Avoid Damage.
- Handle Plastic Gears And Linkages Carefully To Prevent Breakage.
- Test The Unit Before Reassembling Trim Panels: Cycle The HVAC Controls Through All Positions.
- If Fitment Requires Access Behind The Dashboard, Use Proper Tools And Work Lighting; Consider Workshop Assistance If Access Is Difficult.
Order By Part Number A21900100 Or 6447KF For Faster Identification. Suitable For Mechanics And Experienced DIYers Working On Citroën And Peugeot Vehicles With Manual Climate Control.
