Hi.
Driver door stays ajar some times when attempting to close. With repeated tries does close properly. Closing noise differs.
Is there any typical part, spring, component... to check, or the whole lock assembly has to go ?

 

sounds like the latch spring has broken, probably easiest to just replace the whole assembly. check ebay or one of the breakers on here.

 

Exactly, Extinct. Found there is springs at each side of the lever on the actuator assembly that connects to the outside door handle. One found broken.
Cannot find the way to remove its plastic cover to replace it. Very complex mechanisms too.

Suffered a while to remove the assembly from the door. Manual instructions say "remove the linkage to the door handle" but do not explain how it is done. The assembly is wrapped around the glass guide channel which has to be unbolted and bent in order to force-pry the actuator out.
Pictures at section 76.37.12 do not correspond to reality; and there is an extra screw holding the actuator assembly not shown on the manual.