Its unlikely all 3 buttons would fail at the same time though 
True, but if the "ADVANCE" button fails you can't get into diagnostics. I didn't mean I have seen them all fail at once, I meant I have seen 1 stop working many times.
You might be lucky and only one side of the switch has died and you can use the other pole, Try soldering the wires onto the other set of pins on the switch (i.e solder the green wire to the other bottom pin and the orange wire to the other centre pin) It may give you a bit more life out of the switch until you can get another one.
