My switch is similar. I only used center pin and one other pin. I snipped off the 3rd pin.

I did get it working. Oddly, some of the gpio pins only want to work as in or out.

I’m using gpio5 and gpio46 on the switches.

 

root@LEDE:~# cat getsw
#!/bin/sh

echo gpio5
cat /sys/class/gpio/gpio5/value

echo gpio46
cat /sys/class/gpio/gpio46/value

Flipping switches and running above commands a few times, I get…

root@LEDE:~# ./getsw
gpio5
0
gpio46
0
root@LEDE:~# ./getsw
gpio5
1
gpio46
1
root@LEDE:~# ./getsw
gpio5
0
gpio46
1
root@LEDE:~# ./getsw
gpio5
1
gpio46
0