Switch E3 (ID=17673)
The Yellow Toggle Switch
at the square marked
E3
reversez:
the Two-Way Arrowz
in square
M12
.
the Two-Way Arrowz
in square
N11
.
the Two-Way Arrowz 
in square M12.
the Two-Way Arrowz 
in square N11.
at the square marked E3 reversez: