this seems like a
stereo poti to me, no switch
when You get a 3 level / 4 positions switch, try the following:
A, B and C are the contacts in the middle
1 is 1st position for A
5 is 1st for B
9 is 1st for C
when in 1st position --> OFF
2, 3 and 4 as well as 6, 7 and 8 are soldered together.
There goes the current (note: usually these rotaries can stand about 0.5 A, therefore paralleling them is needed)
now for C, which is the external resistor to change output:
9 --> off
10 --> goes to resistor 1,
11 --> resistor 2,
12 --> left floating (here! Else to resistor 3)
thus: an ON/OFF + 3 output levels, single rotary switch