See “setting daytime running lamp mode (usa only) – Mercedes-Benz 2003 S 500 User Manual

2003 S-Class, 2003 S 600, 2003 S 55 AMG, 2003 S 500 4MATIC, 2003 S 430 4MATIC, 2003 S 430, S-Class 2003 Owners Manual