The driver's door locks and unlocks with the key, but does not activate the central locking system. However, locking or unlocking the passenger's door or the trunk correctly activates the driver's door lock. This used to happen only when it was cold outside (rare here), but now it's all the time. What do I need to look for, and is it a moderate DIY job?

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Rick Miley
Tampa, FL
86 190E
87 300E

The door locks on MB are tricky to diagnose because the are part electric and part vacuum, troubleshooting is a pain. I had a similar problem with mine, it turned out to be a bad actuator in the trunk. It stopped the rest of the locks from working. I can tell you of one weak link in the system, I have seen this be a problem on several Mercedes including mine. There is a hose that runs down the right side of the trunk lid from the actuator. It can get a hole in it very easy, that one hole can stop all the locks from working. I just cut mine and got a larger rubber hose to reconnect them. Good luck in finding your weak link. Hope you have the shop manual if you are doing it yourself.

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Adrian Eckenrod
MBCA, PCA, BMWCCA & SCCA* member
86 190 2.3-16
83 944 ITS Racer