Question for those who have converted from 2 to 3 speed wipers

I do want to switch to an electric washer. My original thought was to add an electric washer jar and pump (which I have) and keep the 2-speed wiper motor since I have already refurbished it but I couldn't find any info. on if it was possible or not to have 2-speed wipers with an electric washer set-up on a 69 Dart. The three speed motor I have does have the long brown wire coming from the bulkhead plug on it that goes to the washer pump. I just wasn't sure what to do about the dash switch.