Quoted from Osvivalt:Today I checked the backbox switch matrix board and everything there as well looks as it should in switch 57 area.
Not sure I understand what you mean by this. Could you explain like maybe wiring or the switch does register.
Quoted from Osvivalt:How should I approach this problem?
Well you could start by listening to the switch when you push down. Inside the switch you will here a clicking when activated. Could compare to other switches to make sure nothing came apart inside.Still would not rule out bad switch but a start. The manual can be downloaded off ipdb and if you go into switch test it will show you the color wires associated with that column and row of switch 57 to check the wires since switches are daisy chained. Like the old thread says check diodes.