R129 SL300 ASD warning light and creep current

Hello together, with our SL300 of 93 the ASD warning lamp is constantly on. In addition, the battery is empty after about 2 days and it no longer starts. Do you have recommendations to find the error? Can you recommend us a workshop that can fix these errors in the room Niedersachen / Hamburg / Bremen? What has been checked: -Battery has been tested and is ok. Another battery has also been installed but does not bring any improvement. -Lighting machine is ok -ASD ECU developed and the contacts cleaned -All fuses renewed Thank you for your help! Daniel