Looks like you have a 2 speed wiper motor (like I do), which would make sense with a 3 position (off/slow/fast) switch. But several months ago someone said they had never heard of a 2 speed motor switch (with 3 positions) that had the option for an electric washer motor.
Sure enough, when I messed with mine I found that I had a 4 position switch running my 2 speed wiper.
Just curious if yours is similar or if you in fact have a 2 speed motor switch with the electric washer function.