2010 Mercedes S-Class Owner's Manual - Page 502

500 Unlocking/locking manually Unlocking the driver's door ! When you open the trunk, the trunk lid swings open upwards. Always make sure there is sufficient overhead clearance. X Turn mechanical key ; back and remove it from the trunk lid lock. Locking the vehicle If you cannot lock the vehicle with the SmartKey or with KEYLESS-GO, lock it as follows: X Open the driver's door and the rear left door. X Close the front passenger door, the right rear door, and the trunk. X Insert mechanical key ; into the driver's door lock. X Turn mechanical key ; counterclockwise to position 1. X Pull the door handle past the resistance point until the locking knob moves up. The driver's door is unlocked. X Pull the door handle once more to open the driver's door. X Turn mechanical key ; back and remove it from the driver's door lock. Practical hints i If you cannot close the trunk with the remote trunk opening/closing switch, lower the trunk lid manually and close it with hands placed flat on the trunk lid until it is engaged in its lock. X Unlocking the trunk A minimum height clearance of 5.9 ft (1.8 m) is required to open the trunk lid. Press the central locking switch (Y page 279). The locking knobs of the front passenger door and the rear doors move down. X If the vehicle battery is disconnected or drained: Press down the locking knobs on the front passenger door and the rear doors. X Exit the vehicle. X Check whether the trunk is locked. X If it is not locked, lock it with the mechanical key (Y page 283). Except for the driver's door, the vehicle should now be locked. X Close the driver's door. X X X Insert mechanical key ; into the trunk lid lock. X Turn mechanical key ; counterclockwise to position 1. Enter the vehicle through the rear left door. Press down the locking knob of the driver's door. ! To prevent inadvertent lockout, make sure to have the SmartKey with you before proceeding with the next step. The next step will lock the vehicle.