I searched and saw some similar issues but nothing exactly as this issue. The barn doors wouldn't open from the outside, it felt as if the outside handle was broken, and if using the key - the key could rotate 360 without any clicks or resistance. I did a search in the forums and saw a photo of what was behind the trim and decided to have a go (as you do). I eventually figured out how to override the manual lock which would have solved my problem ( linkage from the rear door manual lock can be disconnected, then only the key fob can be used). It seems as if the rear door lock had been or can be rotated when the key is not fully in and this upsets the logic of the mechanism. The lock barrel operates a push rod which turns a cam shaped arm - when the push rod is disconnected, the lock worked fine. After many iterations of trying to reset this arm & cam, I eventually got it right and everything worked again. Whole job took about an hour...after I succeeded, I wished I had taken photos to share - sorry 'bout that. Any thoughts/comments welcome...cheers