what's that "R" for?
 

I have a very stupid question, I was trying to figure out since I do not have an owner's manual since I acquired the car. On the cluster on each side there is little buttons marked with letter. The left side mark the +/- and a O. which I know that the O is to reset the trip odometer. On the right side it has the H and M for the clock but what's the "R" is for. I was fiddling with it and it doesn't show or do anything. Anyone have a clue what that is? Mine is a 96' E320

The "R" is for reset when a message on dash comes up, like faulty light, etc

press to reset odometer or cancel FSS

On mine,you hit it twice and hold it to reset the mileage when the total miles and trip miles are shown.