Wiper Motor





Hi this motor is from a mid 90's Van my family once had. I pulled a couple parts off of it before we scraped it. Anyways I have been trying to see if I could get this motor to work on my duster and am kinda a newbi with wiring. This motor is has four pins, two are yellow and black the others are not color coded. When I connect the yellow and black (+ and - respectively) the motor runs, however I would like to know how the other speeds are engaged.

Any incite would be awesome Thanks,
Jacob