How to Test a W123 Vacuum Door Lock Actuator

Easy to test when out of car. See Kent's manual to learn how to test without removing door panel.

Doors won't lock or unlock. It could be a failed door lock actuator. Check out Kent's YouTube video. It will explain how they operate and how to test them with a vacuum hand pump tester. This tester is essential if you are going to attempt to fix your door locks on your own. You can save hundreds $$$ by doing it yourself. 

Sometimes it is just a leaking actuator. Other times it can be a combination of problems that can drive you crazy. See Kent's manual on how to troubleshoot and repair the system on a 1977 to 1985  240D, 300D, 300TD, 300CD, 280E, 280TE and 230E 

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Problem & Solution

Common among these chassis: