2010 Mercedes S-Class Owner's Manual - Page 504

502 X Replacing batteries (SmartKey, remote control, headphone) Firmly press the head restraint cushion backward towards the head restraint cover in direction of arrow = until it engages. X Repeat this procedure for the second front seat. X After resetting the NECK-PRO active front head restraints store reset tool : in the Mercedes-Benz literature pouch. For information on NECK-PRO active front head restraints, see "NECK-PRO active front head restraints" (Y page 55). For information on head restraint adjustment, see "Seats" (Y page 286). SmartKey When inserting the batteries, make sure they are clean and free of lint. When replacing batteries, always replace both batteries. i The required replacement batteries are available at any authorized Mercedes-Benz Center. Replacement batteries: Lithium, type CR 2025 or equivalent. X Remove the mechanical key from the SmartKey (Y page 499). Replacing batteries (SmartKey) Practical hints Replacing batteries (SmartKey, remote control, headphone) Notes If the batteries in the SmartKey are discharged, the vehicle can no longer be locked or unlocked. It is recommended to have the batteries replaced at an authorized Mercedes-Benz Center. G Warning! Batteries contain poisonous and corrosive substances. Therefore, keep the batteries out of reach of children. If a battery is swallowed, seek medical help immediately. X Press mechanical key ; into the SmartKey opening until battery compartment cover : opens. Do not keep the cover shut. G Warning! SmartKey batteries contain perchlorate material, which may require special handling and regard for the environment. Check with your local government's disposal guidelines. California residents, see www.dtsc.ca.gov/ HazardousWaste/Perchlorate/ index.cfm. Batteries contain materials that can harm the environment if disposed of improperly. Recycling of batteries is the preferred method of disposal. Many states (USA only) or provinces (Canada only) require sellers of batteries to accept old batteries for recycling. X X Remove the battery compartment cover. Pat the SmartKey against the palm of your hand until battery = falls out.