explanation on how 2 speed wiper works

By my parts manual, I believe the switch you need is a 2864415, lists it as a 2 spd. I would assume all would have the washer function??
Also here is a link that may help...not sure. I just did a search with that part # in fabo search box.

http://www.forabodiesonly.com/mopar/showthread.php?t=183213&highlight=2864415