Central lock system

1999 MERCEDES BENZ ML320
15,234 MILES
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CHARLES PIUSON
  • MEMBER
  • 2 POSTS
When I lock from the driver's door of ml 320 Mercedes Benz the other doors do not lock and yet if I press the central lock button in the car all doors lock up together what might be the problem with the central lock system of the car. How is a central system of that car controlled. How many relays does it have and where are they located, how are their connected to one key lock at the driver' s door?
May 10, 2016 at 3:06 PM
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STRAILER
  • CAR REPAIR CONTRIBUTOR
  • 54,360 POSTS
Hey CHARLES,

It sounds like you have a problem with the door key switch which has connects that control the other doors. There are no relays just a central controller. Here is a wiring diagram, I would start at the drivers side door lock switch first

Let me know how it goes

Best, Ken
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May 11, 2016 at 7:22 PM
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