Inside manual door lock not locking or unlocking door

I wasn’t sure how to describe this problem in the title so I hope I can get some help from others that have possibly had this same issue. So all the power locks function as they should locking and unlocking the doors, the problem is on the passenger door you can’t just lock or unblock the door with the inside manual latch, you have to use the power locks to unlock the door. The door lock doesn’t move when the power locks are used. Hope this makes sense, any ideas?

 

Failed unlock cable, cable holder or both.

 

Thank you for the diagram, I guess I won’t know for sure until I take the door apart. This is strange as that manual lock was so seldomly used

 

Vibration can cause bolts and nuts to loosen. It's like magic, especially on a motorcycle.

 

I kind of feel that’s what I may find, the handle was rarely used and never abused