Hello together, I recently added an SL500 from 2002, the vehicle has almost full equipment (Keyless-Go etc.) The problem: If the vehicle is 2 – 3 days without starting in the garage the battery is empty. I bought the car the other day, already with the previous owner it showed the battery indicator in the display. Then a good used battery 74 Ah bought the same, fully charged and mounted in the back of the trunk. Thought everything would be okay, now I noticed that the problem still exists. Have a Bosch ESI tester, which shows me only a fault memory currently: Air conditioning multifunction sensor error in the data bus Another deficiency is: that the seats (massage function etc.) driver and passenger do not work. Should be over the air line under the passenger seat, I also hear an air noise or hisshy. What do you mean? Why does the battery go so quickly empty? Where do I have to start looking for the error? Is that the main reason with the sitting? I can still start the vehicle when I take out the key and then do not start a problem again for the battery.