One problem related to wiper has been reported for the 2012 Mercedes Benz ML350. The most recently reported issues are listed below.
The conrol to activate the windshield washer is a stalk mounted button on the left side of the steering wheel. Pressing this button will correctly cause the windshield washer to come on briefly, spray the windshield with water and follow up with a few strokes of the wiper to clear the windshield. The problem with this arrangement is that the similarity of the button on the end of the stalk on the right side, which places the transmission in park. Thus if you are traveling on the interstate, for example, you could easily confuse going into park with washing the windshield. My experience if you make this mistake is that the car will not go into park while the car is in motion, but will go into into neutral until the car fully stops. This could be a dangerous maneuver, especially in the rain on a busy interstate. This button and its placement should be improved to correct this confusion.