I guess it says f on the dash? as they go quite often on the older a class chassis 168, you have to take all the centre console but out the. there's 4 Allen keys that go around the gear module, then a cable which has a clip mechanism on it from under on the box, they don't need to be programmed either. it's a lot of messing around as need to take ash tray out hand brake leather loads of hidden screws etc. but can be done pretty quickly