S 420 (140.043) V8-4.2L (119.981) (1996)
Air Door Actuator / Motor: Description and Operation
Vacuum Element For Blend Flap
The blend flap vacuum elements actuate the blend flaps (air from the heater core) for control of the air to the center nozzle.
The blend flap vacuum elements are designed as single stage vacuum elements.
Function
The blend flap vacuum elements (45, 46) are actuated automatically with the valve block (Y11) via the control pushbutton module depending on the
temperature in the heater core.
In the open state vacuum is present at the blend flap vacuum elements (45, 46). When changing from cooling mode to heating mode or vice versa (mode
change) the blend flaps are opened for a short time.
Manual hot/cold switchover on center nozzle
If the "hot" button on the center nozzle is pressed, the blend flaps are opened regardless of the temperature in the heater core. Pressing the "hot" button
again reactivates the automatic mode for the blend flaps.
If the "cold" button is pressed in the "hot" mode the blend flaps close.