How do you replace the door lock of the Mercedes C-Class?

Disassembly and replacement of the lock of the Mercedes Class B.

How To Restore Door Lock Beep On 2005 Mercedes E320

This is another failed Turbo Actuator solenoid, Mercedes want us to replace the entire turbo and actuator as one... that's thousands of dollars and very unnecessary, We've found that getting these units repaired is the most cost effective and reliable way to fix the issue and it saves our customers a fortune compared to the dealer recommended fix. | Eurostar Diesels

How to identify a defect in the electronic actuator of the Mercedes Benz C-Class w203?