2008 Mercedes CL-Class Owner's Manual - Page 710

Practical hints Jump starting Remove red cover from positive terminal 4. Connect positive terminal 3 of the charged battery with positive terminal 4 of the discharged battery with the jumper cable. Clamp cable to charged battery 3 first. Get into vehicle and start engine within 30 seconds. If the starting attempt does not succeed: Turn the SmartKey in starter switch to position 0. Take out the SmartKey. Turn off engine of donor vehicle, restart it and let it run at idle speed for several minutes. Disconnect the jumper cable during this time. Reconnect jumper cable as described before. Restart engine. While the engine is running, switch off several electrical consumers such as the blower. Disconnect jumper cables first negative clamp 1 from ground point and negative terminal 2, then from positive terminals 4 and 3. Have the battery checked at the nearest authorized Mercedes-Benz Center. ! Never invert the terminal connections. Connect negative terminal 2 of charged battery to jumper cables and attach other end of the jumper cable with the negative clamp 1 to a suitable ground point on the vehicle. 709