dtownkennel

I have a 09 ml550 where the driver side lock doesn't work. The electrical seems to work bc I can hear it but just doesn't lock. I am hoping it's a spring or something that is broken.

I have taken the door panel off but cannot seem to take off the metal panel underneath. I unscrewed everything and it's loose but won't come out. Has anyone taken this off before tell me? I have a feeling it's the window but can't even get to it.

kerunt

If your door lock was bouncing up and down as you tried to close it, then it's a problem with the door lock actuator. I had the same thing myself. The problem is in a tiny spring - it breaks and needs to be replaced (ebay - $5).

Taking off that metal panel is a PITA - it's riveted down, and you have to drill the rivets out. You'll obviously need a rivet gun (~$30-40 at Home Depot) and new rivets (can't recall the size/metal, but do a search for "ML lock actuator" on Google and you'll find other threads that will give you those details.

dtownkennel

Thanks for the reply!!

Man I really don't want to drill out the rivets but if that's the only way to get it out.
Is it also attached to the window as well?

My lock doesn't bounce up and down it just doesn't move at all but you can hear the electrical work though.

Thanks!

kerunt

Drilling is the only way. Dealerships will do the same thing.

From what I can remember, there is a long, white, plastic piece (regulator, I think) that is attached to the metal - this has the window "wire" coiled up around it, but other than that, the window is not attached. I vaguely remember not taking the entire metal piece off, but rather prying the actuator partially out - just enough to get at the spring.

Also, once you disconnect the window, you'll note that you will lose the auto down/up option. There is a procedure for "re-learning" the window up/down mechanism - I can't recall what it is, but it's simple and takes a few minutes.

CLK Group

Dealerships will likely replace, not repair. My Indy charged $600 ($400 for the whole part, $200 labor).

As I recall, the re-learn procedure is to turn your wheels full right and then full left while running.

kerunt

Dealership will replace the actuator, yes. The indy I spoke with (prior to doing the repair myself) wanted to do the same thing, otherwise they can't warranty it.

I looked up the re-learn procedure I did: key into first position (accessories), roll up the window and keep holding the button for two seconds.

dtownkennel

Thanks guys!

dtownkennel

So I've been so busy I haven't time to change the lock on the driverside. Today I turn on my seat warmers and the locks end up working and does not work of the seat warmers are turned off. Any ideas of it's a fuse?? It's definitely a electrical problem, wondering if anyone has any idea what causing it.

Thanks

khutchinson22

You have a ground short somewhere it sounds like. I would locate a wiring diagram and figure out if the wires are run near each other. My ML is not equipped with heated seats so I don't know if the switch is in the door or on the dash panel. If it's in the door, I would take the door panel off and see if the wires are touching somewhere. The problem might be in the accordion between the frame and the door (where the door hinge is). This is a common place for wires to deteriorate due to constant movement.

flybd5

Oh brother... only German engineers would design a door locking system that requires drilling out rivets to R&R an actuator (or a headlight bulb that almost requires a trip to service to get it replaced, or door buttons that fail in year model after year model and are not recalled or redesigned, or... Meh. The list goes on and on.) Quite frankly, owning a Merc has completely destroyed my belief in the myth of "superior German engineering..." The VW scandal was just the last nail in the coffin. Next time I'm getting a Land Cruiser.

flybd5

FWIW, the solution to the door handle buttons that don't work is to hit them with a hair dryer or other source or hot air until they completely dry out internally.