In the event of a rear collision, certain Mercedes models are equipped with safety rear headrests. These headrests are designed with Neck-Pro technology, which causes them to more forward and offer neck protection. Once the headrests have moved, however, they must be reset in place before they can be adjusted normally again.
Remove the resetting tool from the wallet of your User's Manual.
Insert the tool into the guide located between the head restraint cushion and the head restraint's back cover.
Press the tool downward until you hear the restraint deployment system re-engage.
Remove the tool and push the headrest back until you hear it engage.
Repeat these steps with the other headrest.