Take time to view through the "ML" forum and see the list of recurrent problems people have had with this abomination.
50 ML Problems in 4 Years.
I had to return the vehicle on 20 or more occasions to Autonation (the dealer) for warranty repairs. All Mercedes is willing to offer as compensation is $1000, when purchasing a new Mercedes. Despite the many defects Mercedes Benz has not offered to repurchase the car.
The problems included a defective brake system, a defective electrical system, a defective navigation system, a defective washer system, a defective AC system, defective locks, defective trim, defective doors, windows and sunroof and a defective entertainment system.
In addition it often took 1 month to get the vehicle serviced. Often the dealer did not fix the problem on their first attempt, resulting in having to return the vehicle again for repair of the same defect.
I have attached a more detailed list of the problems below.
I get the impression that 1 out of 4 have many problems (not a formal survey).
50 Mercedes Problems in 4 Years
1. Brake system defect (pump leak)
2. Wiper motor defect
3. Door problems (latch noises)
4. Door problems (maladjusted door)
5. Command center malfunction (dead navigation system)
6. Door lock malfunction (right rear door actuator)
7. Washer reservoir leaking
8. Lamp switch defect (stop lamp)
9. Fuel filter problem
10. Door lock malfunction (gas door actuator)
11. AC problem. (AC fan speed switch knob malfunction)
12. Door lock malfunction (gas door actuator)
13. Trim problem (sunroof seal fell off)
14. Door problem (Rattle from inside left rear door - loose metal washer)
15. Trim problem (3rd brake lamp cover pops off even when re-secured
16. Trim problem (rear inside trim panel defective)
17. Window washer nozzle defective on right side
18. Command center malfunction (dead navigation system)
19. Door lock problem
20. Lamp problem (defective check engine light - right rear 02 sensor)
21. Rotor in rear changed at only 27500 miles
22. Sunroof shade problems
23. Sunroof guide clip missing
24. Sunroof shade problems
25. Trim problem (left outer seat trim cracked)
26. Sun roof frame defect
27. Seatbelt jammed (left rear)
28. Brake system defect (pad wear sensor defect)
29. Defect fuel door lock actuator
30. Rear door latch replacement
31. AC problem (system not cooling properly)
32. Sunroof motor connectors rattling
33. AC problem (blower motor rattle)
34. Window problem (switch bad)
35. Command center problem (CD changer error)
36. Window problem (clicking front left window)
37. Door lock problem (rear right/left door actuator defect)
38. Door problem (insulation inside right door damaged due to melting glue)
39. Command center problem (CD changer error)
40. Trim crack (leather on steering wheel cracked)
41. Door problem (rear right/left door actuator defect)
42. AC problems (blower rattle)
43. AC problems (clicking sounds)
44. Trim crack (cracks in duct tape on door)
45. Door problem (rear left door actuator defect)
46. Washer reservoir crack
47. Right window washer nozzle defect
48. Lock problem (front left door actuator defect)
49. Car manuals taken from my car during service
50. Power steering problem (replacement of clamp for power steering hose due to possible fluid loss at radiator)