Is this not a feature of the ML ? I can't find the lock anywhere on the rear doors of my ML nor it mentioned anywhere in the owner's manual.

it is electronic. i think the same switch that turns off the rear window controls affects the way the rear door locks function. there is a switch near the gear shift. when the switch is (to the left, i think) allowing a dot to appear the rear doors are not locked. when the switch is in the other position (a small person appears), the doors can not be opened (or, at least, must be manually unlocked before being opened).

Aha! No wonder my daughter fusses at me about not being able to get out of the ML when the locks are engaged!

That would mean however, that the childproof locks are only functional IF the console switch is set AND the doors are locked...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

yes, but your doors lock automatically after you reach 9 or 10 mph (if you have programmed them to do that).

Was programmed that way when new, but the dealership eventually disabled that feature as it was not intended for use in that model year. There were problems with unintentional locking back then...happened twice.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

But also keep in mind that the front doors can be opened from the inside at any speed, even if previously locked by any means - manually or electronic. This action will automatically unlock the rear doors thereby disabling any built in safety. Why MB does it this way is a mystery to me. I guess they believe that no sane adult wlll dare open the front doors while the vehicle is moving - I disagree with that logic. In other vehicles I've had (Nissan, Honda, Acura), once the doors are manually locked, you can't open them from without manually unlocking them.

ON my 2001 ml320,
I tried that trick to activate the child saftey locks. I can still open the doors from the inside when the windows are locked. Still doesnt work. Maybe this was a feature only on the earlier models?

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2001 ML 320 (silver)
1999 E320 (smoke silver)
2002 Acura TL Type S
1994 Honda Civic EX (commuter)

I have a My02 320 and 01E430 and on both, you can unlock and open the front doors while in motion, regardless of the way they were locked. The rear doors will, however, not unlock unless the fronts are. And of course, there's no warning to let the driver know that any of the doors are unlocked!!!!