The rear hatch lock on my 1981 300td has always worked with the key but has never worked with the central locking system. I removed the rear interior panel today and found that the vacuum actuator is actually working fine but the actuator rod has come disconnected from the hatch lock assembly.

I'm trying to figure out where the actuator rod connects to the lock assembly. It looks like there might be a few places where it could connect (see pic below for one of the places I'm thinking), but I'm not seeing how the rod would secure to the lock assembly. I'm wondering if a plastic part may have disintegrated.

I've been looking for a good diagram or picture but haven't found one yet. Does anyone have experience with this that might be able to give me some tips.