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Door Locks Cycle Rapidly Mercedes Benz ML320 ML430 ML500 ML350

Are your Mercedes Benz ML door locks moving up and down rapidly on your ML? This is also known as the Machine Gun Locks problem.  This happens because the actuators in one of the doors are defective. The plastic tappet plate component inside the actuator has broken. You can try replacing the whole actuator or the broken part inside it. Watch the videos at the end of this article if you want to perform this repair. In the meantime, you can disable the automatic locking and, thus, the annoying rapid locking/unlocking of the doors.

Estimated Repair Cost: $300-$400 performed by a Mechanic. If you do Do-It-Yourself, you are looking to spend under $200.

Parts:  You can get them from these sellers for much less than the dealer.

Affected Models: W163 1998 – 2005 ML-Class
ML-230  ML-270 CDi ML-320 ML-350 ML-400 CDi ML-430 ML-500 ML-55 AMG

Temporary Solution:  Disable the auto lock feature on the ML. The ML is programmed to lock the doors when you start driving automatically.  By disabling the automatic lock function, the car won’t try to lock the doors automatically.
Do this:

  • Turn the key to position 2; all your cluster lights are on. Don’t start the car yet.
  • Now press the unlock button in the center console to lock the doors for at least 10 seconds, disabling the auto-lock feature.

Or watch this video to see how it is done.

The Problem: The actuators for the individual doors get damaged and jammed, thus not responding to the motor when it tries to lock or unlock the door. When using the keyfob or the dash button for locking or unlocking the doors, the jammed door actuator tries times to complete the lock/unlock action.  Since the micro switch of the damaged door did not report a Locked /Unlock status to the All Activity Module (AAM), the AAM unlocked and relocked all the doors repeatedly until all the doors (micro switches) reported the Locked status.ml door actuator

Solution: Replace the door lock actuator; door locks will function normally again.

You can get the door lock actuator for a fraction of the dealer prices from Amazon to see here. 



1.) Determine which door has the broken actuator.

  • Manually unlock all the doors. Lock your doors. One of them will still be unlocked.
  • Manually lock all the doors. Now unlock them. One of them will still be locked.
  • If your doors work properly, check the lift (trunk) gate.

2.) Remove the cover from the door handle using a flat screwdriver. Once you do that, you will see two Philips screws.

3.) Remove two bolts located inside your door handle

4.) Pull out the SRS Plastic Logo. Then unscrew the last bolt located under the SRS plastic logo.

5.) The door panel is held in place with push-in pins. Pry off the door panel in place.

6.) Detach the light wire plug located underneath your lower door lamp

7.) Disconnect the other wires. One is the actual door lock the other goes to the speaker.

8.) Roll up your window.

9.) Locate the hole at the edge of your door.  It is covered by a rubber drain seal that prevents water from entering the edge of your door, directly lined with your door handle from the outside! Use Torx “T27” and unscrew the bolt directly leveled with the entrance cavity. Hint: You do not need to unscrew it all the way. Just loosen the grip that is holding the plastic door handle cap outside.
10.) It is time to remove the door handle outside the car. Remove the plastic cap from your door handle.


11.) Carefully slide the rest of the door handle back. You will be pulling the door handle towards the back of the car.

12.) When you remove the door handle, you will see 2 new bolts. Loosen them but do not remove them.
13.) Remove the black plastic used as noise insulation. You peel this plastic off.
14.) Now remove your door latch. It has two Torx bolts.

15.) Now, it is time for you to pull the old actuator out and install the new one. This is the tricky part, but you can do it. Once you install the new actuator, don’t bend the window guides. If you did, set them to their proper position, or your window will not go all day or down slowly.

16.) After installing the new actuator, you finish the hard part. Everything goes in reverse order.



Mercedes w163 (late) Door Lock Mechanism Right Rear OEM locking actuator latch
Part# 163 730 28 35


Mercedes w163 (early) Door Lock Mechanism LEFT Front lh driver side latch actuator
Part# 163 720 25 35
Mercedes w163 (late) Door Lock Mechanism Left Rear OEM locking actuator latch
Part# 163 730 27 35
Mercedes w163 (late) Door Lock Mechanism Right Front OEM locking actuator latch
Part# 163 720 32 35


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