Seems like it's working as it should - with the key out, door switches work if a door is open, don't work if the doors are closed. Has nothing to do with the lights per se but the lights might be triggered by the same switch. With MBs 2 inches ajar or less is considered closed. In older MBs the window switches work when the doors are open. I haven't tried with newer MBs.

Always bugged me that MB switches aren't as sensitive as Japanese car switches. Japanese car cabin and warning lights stay lit until the door is fully closed. With an MB the door can be only at the first catch and nothing tells you the door is ajar othat than it won't lock.

Sixto
93 300SD