Mercedes-Benz C-Class 2014 Owner's Manual page 386

Using the 230 V power socket
To switch on: switch the ignition on.
X
Open flap =.
X
Insert the electronic device connector into
X
230 V power socket :.
Indicator lamp ; lights up.
To switch off: remove the connector from
X
230 V power socket :.
Make sure that you do not pull on the cable.
Features
383
Z