Wiper Switch Problem

Maintenance/Repairs
1 
            The wiper switch, located in the directional lever, in my 1992 Buick Century broke. Fortunately, it broke while in the "on" position and there is a 25A fuse dedicated only to the wipers. No other accessory is on this fuse. I was able to make a quick fix with an external switch / fuse box that rests on top of the dashboard and plugs directly into 25A fuse socket.
I don't want to suffer the time and the expense of getting an exact replacement. I would like to make up a switch assembly that bypasses the original wiper switch instead of having one that merely feeds power to the whole wiper circuit. Attached is a wiring diagram, but I can't figure out how the wiper switch works in conjunction with the wiper motor. 
To analyze the problem, I removed a 6-pin connector from the wiper motor, and powered up the circuit. The wiper blades retreated to their lowest position but went into a short jitter stroke as if they were trying to start. Apparently there is another connector hidden someplace. I measured the voltage at each connector pin with respect to the body. At one extreme pin (I can't tell if the wire is purple or pink) I measured 13.3V. At the other extreme pin (wire is white but not indicated in the diagram), I measured 21V. All the connector pins in between measured 0. 
Are there any automotive electricians in the Car Talk community who can tell my how the wiper switch is supposed to work so I can model a close replacement?
2

Calling Rube Goldberg… Calling Rube Goldberg… Report to Car Talk Mr Goldberg.

3

You will wast MORE time and as much ‘‘expense’’ fooling around with it.
Just buy a new switch and install it. The directional lever simply reaches down to the wiper switch which is a separatte unit. McParts stores have them for about $ 70 some bucks depending on options.

4

Ken,
Do you mean there is a mechanical linkage from the lever down to the switch?

5

The lever cames apart from the switch. the switch lives down inside and twisting the lever works it.
Look at pictures in the parts house websites like Autozone.com and Rock Auto.

6

The junk yard is your friend, but hurry, there aren’t many 92’s left except in pull your own lots.