Check you contacts under the buttons, mine were JUST making
contact. Burnish them up good and maybe adjust the blades to give
you a bit more contact. Also the two buttons have a circuit in series
i.e. the contacts of one(I believe the Left button) must be NC to get
the right button action. So check the left NC contacts.
Not having the schematics in front of me right now, it may be the right
one but I believe it is the left one.
Good luck
Terry K