Hi, I am having the same problem as Rob with his 4MATIC LIGHT LIT and he mentioned the STOP LIGHT SWITCH. Where is this and how difficult is it to replace!! I'm pretty mechanical so I hoping this can be done at home.

You have to remove the driver's side under dash panel and get on your back to see it. It is located on the top portion of the brake pedal lever.

You have to push a tab and twist to take it out. You will need to pull the lever out on the new one to do the self adjustment.