rain sensing wipers

Hi everyone, when i bought my car i had these parts in the trunk, it seems the prevous owner removed them. i took pictures but dont know how to post them. Its a little black box and a cover. Not sure if im missing anything or how to hook it up as theres one wire near the mirror but its already connected to a connector? Any help?

Ok, update, found the wire connector tucked into the headliner. but i still think im missing a part that goes inside the little black box?