If I might add to Grant's post;
you may use a stock Ford dash knob (as I did on the Galaxie) instead of the black knob that is supplied with the switch. CLICK HERE
for my electric wiper retrofit.
This is a great improvement to your car. The vacuum wipers are terribly insufficient and weak compared to the electric. Correction: There IS no comparison. It's like comparing disk brakes to shoe brakes. Once you convert, you will never go back. - Dave