Odometer not working all the time

[brendo]

My odometer does not work all the time I use to hit the top of the dash to get the km to come up but the last week it has been come up weird where you can't read it. If I move the button to one side it would show up so I pulled the dash out last night and the little white button behind the the button to change the odometer seems to be loose has anyone had this problem and how did you fix it