The oem harness is about 69 inches long end to end. The connector by the mirror is 1/2" long by 3/16" wide, and gets pointy on the top. The other end (inside measurements, not to the outside of the plastic housing) is 3/4" wide by 1/2" high.
Take careful note. It's the 2nd connector, not the one on the outside of that box, but the one towards the middle... It looks the same, but there's no wires attached to the outside one.