My sliding side door had a problem a couple years ago where if the door was opened all the way to the point where it latched open, it had to be closed from outside because the inside door handle wouldn't work. It worked fine for opening the door, just not for closing it. The outside handle still worked for both opening and closing. The problem was fixed at my Sprinter dealer when I had the van in for Schedule A service, but the problem came back not long ago; whatever they did to fix it apparently came undone.
I added an intermediate stop on the center roller track so that now I only open the door partway, so now it's mostly a non-issue. Memo to self— don't forget to have MB dealer fix it again at the next service interval…
Engineering: Finding complex solutions to simple problems you didn't even know you had.