I have ml320 bought Car everything ok for a week then wipers front rear would not work it went away the mechanic managed to break the wiper switch while replacing this he broke a sensor under the steering wheel replaced this got car back everything seemed ok and then wipers would not work again but started again key rf now not working reverse lights not working and odd things all electrical but the most annoying thing is there is no kickdown the car pulls away ok and cruises very well but I can't overtake anything no oomph I think it is all connected to the electrics and probably a bad earth but where do I start and what does s a m stand for thanks in advance for any help oh by the way it is a 2006 model.

 

This appears to be a common problem on the w163 ml that is usually associated with too much play in the gas pedal. This results in the pedal not making contact with the switch that sends the signal to the transmission when you press down hard. The most common cause is a worn plastic pivet pin in the gas pedal that can be replaced very cheaply - this used to be a B service item. Several people on other forums have said that they have solved this problem by changing the plastic pin for an 10 mm bolt. This makes the pedal more stable.

 

You can check the kickdown switch also, I believe they have adjustable pin/plunger height to be reached by gas pedal and make the contact.