Fresh air/recirculated air flap, function - GF83.20-P-2104-02S

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Function

When the system is switched to recirculated air on the pushbutton control module ( , LED illuminated), the main air flap is closed by the main air flap vacuum element and simultaneously the recirculated air flap is opened by the recirculated air flap vacuum element. Air is sucked out of the vehicle passenger compartment into the automatic A/C housing by the blower.

There are basic differences between the manual and automatic recirculated air mode.

Manual recirculated air mode

When the recirculated air pushbutton is pressed ( , LED illuminated), the system switches over to 100% recirculated air for a limited time under the following conditions:

for 30 min. at an outdoor temperature of >7 °C
for 5 min. at an outdoor temperature of < 7 °C
for 5 min. when the EC mode ( , LED illuminated) is selected.
Automatic recirculated air mode

The automatic recirculated air mode is not indicated by the LED function indicator.

After switching the ignition ON 100% recirculated air is possible for a maximum of 30 minutes; after expiration of this time or after dropping below the 100% threshold the system switches over to 80% recirculated air. After switchover the automatic recirculated air mode is no longer possible even when the 100% threshold is exceeded again.

100% automatic recirculated air is possible when automatic 100% recirculated air mode was not present before expiration of 100% manual recirculated air.

Automatic recirculated air mode with fog sensor (code 306)

Automatic switchover to recirculated air by the fog sensor is possible when

the activated charcoal filter pushbutton ( ) is pressed (LED illuminated)
the AC compressor is operating (not EC mode, LED not illuminated)
s have passed since switching on the ignition (heat-up time for fog sensor)
and the outside temperature is > 7 °C.