My W221 fuel filler door lock actuator seem not working, luckily that actuator is in open position. Is there any one encountered with similar problem and how to repair? is there any fuse or really to check? I wanna to remove actuator out but I don't know from where I need to access actuator for removal, do I need to access from the trunk or I need to access it from fuel filler door?

I'm success to find procedure to remove and install fuel filler flap central locking on WIS, attached here for your info.

You can gain access to wiring by removing trunk panel.

Access fuel filler door lock actuator from trunk then you can able to access emergency handle to open fuel door but will not able to remove actuator out for repair and replacement. For actuator removal we need to remove from fuel door filler as procedure i share earlier.

attached a few photo of the actuator for detail.