This switch costs a fortune to buy nos or good used. I found this out when I restored my dash in my 68 Cuda. Same switch as yours. Mine would only run in high or off mode. I took the back off the switch and found that the old grease in it had hardened up over the years and affected the operation of it. I sprayed it with some electrical contact cleaner , greased it with dielectric grease and reassembled it. Worked perfect after !!
If your switch is not working , it costs almost nothing to try this before you spend money on a new one. Hope this helps!!
