Use a 1-1/16 inch wrench or an adjustable wrench to loosen the wiring harness cable's strain relief fitting from the switch housing.

Once the fitting is loose enough to turn by hand, twist the wiring harness cable and fitting counterclockwise until it is fully unthreaded from the switch housing.

You may need to rotate the switch assembly itself since the wiring harness cable is connected to the device, preventing it from rotating freely.