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Q: Automatic door locking system issue

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My car has an automatic door locking system. Lately, it started malfunctioning. I had a fuse replaced and now it works but only intermittently. How can I fix this permanently?

A Mercedes of your model year use a combination electric/vacuum door lock system. The fuse was for the electrically powered vacuum pump only. The rest of system uses rubber vacuum lines which leak when old. You can replace them one at a time as they fail or leak, or all at once - a more expensive, but one-time repair. A YourMechanic professional can help diagnose the locks and repair this problem.

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