Mercedes-Benz SL Roadster 2012 Owner's Manual page 146

Activating/deactivating
Example: ¿ button
To switch on: press the ¿ button.
X
The indicator lamp in the ¿ button lights
up.
To deactivate: press the ¿ button.
X
The indicator lamp in the ¿ button goes
out. The "Cooling with air dehumidification"
function has a delayed switch-off feature.
Operating the climate control system
143