The heater damper motor reducer and its position sensor are made in a single unit.
You will need a Phillips screwdriver.
1. Disconnect the wire from the terminal «minus» battery.
2. Remove heater (see «Removal and installation of a heater radiator»).
3. Remove the three screws securing the gearmotor unit to the heater housing..
4.... and remove the block and heater damper position sensor.
5. Install the parts in the reverse order of removal.