Look inside your door for a little broken plastic thingy (technical term
)
now look on the other door where that little plastic thingy is supposed to be. That's how I figured it out on mine.
The part may be called a "Sleeve Lock" and the part number might be 62101PA081 but that's just what I got from a thread in the "Wanted or For Sale" forum.
I actually ordered the part today because I'm curious if that's the right one or not.