Wiper motor and switch, 47 Lincoln

[pwlovely]

My car is a 1947 Lincoln 76H Coup convertible. I purchase a rebuilt wiper motor. I am having difficulty getting the wiper to work. I bypassed the wiper switch, connecting the vacuum line directly to the wiper motor, and closed off the return line. No action from the wiper. Was this a correct method of testing the wiper motor?

 

I have attached a picture of the wiper switch. There is a metal cover and a piece of cardboard. The two are meant to cover the holes at the top of the switch. But they do not fully cover all three holes. Part of an end hole will not be covered, depending on how you align the metal cover and cardboard. Should the holes be fully covered? When I turn off the car I can hear air escaping from the switch - as it is presently configured.

 

I'm trying to determine if the switch or switch cover is bad, or the rebuilt wiper motor.