2008 Mercedes SL-Class Owner's Manual - Page 354

Practical hints What to do if ... Problem Possible cause/consequence During driving the red seat belt telltale flashes and you additionally hear an intermittent warning chime with increasing intensity. The vehicle's speed once exceeds 15 mph (25 km/h) and you and/or your passenger have forgotten to fasten your seat belts. There are items placed on the passenger seat and therefore the system senses the passenger seat as being occupied. Suggested solution Fasten your seat belts. The seat belt telltale goes out and the warning chime stops sounding. Remove the items from the passenger seat and put them in a safe place. The seat belt telltale goes out and the warning chime stops sounding. < i After 60 seconds with an unfastened seat belt, the warning chime stops sounding and the seat belt telltale illuminates continuously. The seat belt telltale will only go out if both, the driver's and passenger's seat belt are fastened, or the vehicle is standing still and a door is opened. 353