2005 Mercedes S-Class Owner's Manual - Page 411

Practical hints Towing the vehicle ! To be certain to avoid a possibility of damage to the drive train, however, we recommend the drive shaft be disconnected at the rear axle drive flange (vehicles with 4MATIC: disconnected at the front and rear axle drive flanges) for any towing beyond a short tow to a nearby garage. If the SmartKey is left in starter switch position 0 for an extended period of time, it can no longer be turned in the switch. In this case, the steering is locked. To unlock, remove SmartKey from starter switch and reinsert. i To signal turns while being towed with the hazard warning flasher in use, turn SmartKey in starter switch to position 2 and activate the combination switch for the left or right turn signal in the usual manner - only the selected turn signal will operate. Upon canceling the turn signal, the hazard warning flasher will operate again. Warning! G Warning! G If circumstances require towing the vehicle with all wheels on the ground, always tow with a tow bar if: the engine will not run there is a malfunction in the power supply or in the vehicle's electrical system as that will be necessary to adequately control the towed vehicle. Prior to towing the vehicle with all wheels on the ground, make sure the SmartKey is in starter switch position 2. With the engine not running, there is no power assistance for the brake and steering systems. In this case, it is important to keep in mind that a considerably higher degree of effort is necessary to brake and steer the vehicle. Adapt your driving accordingly. i The gear selector lever will remain locked in position P and the SmartKey will not turn in the starter switch if the battery is disconnected or discharged. See information on the battery ( page 403) or on jump starting ( page 406). 409