There is a guy who lives near me who is the local 'backyard mechanic' i:e he messes with other peoples cars on his driveway and charges them for the privilege. He told me that you can re set any fault codes or 'dash' lights on older (not sure how old, pre OBD 1996 ?) Mercedes Benz cars by disconnecting the battery and shorting out the positive and negative leads for 30 seconds. Anyone heard of this ? I have no intention of trying it, just curious.