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

Practical hints Towing the vehicle ! To be certain to avoid a possibility of damage to the transmission, however, we recommend the drive shaft be disconnected at the rear axle drive flange for any towing beyond a short tow to a nearby garage. Warning! G 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. 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 SBC brake system 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 certain that the SmartKey is in starter switch position 2. 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. 409