I had to replace 3 of these plus 1 was fixed under warranty.

Do you know how I fixed it? I don't put the back windows down. After the regulators are 1 year old the white connector fails. I told Mercedes that this was an engineering defect. They called the factory and said 'no'. I asked Caliber how many they fixed each week. They said 14. Seems like a defect to me. Maybe it is to keep kids in the back seat from getting their arms stuck in the window.

Also, I have gone through 3 air mass sensors. They seem to go out when I am in the mountains.

Do you want to know how I fixed it? I don't take the Benz to the mountains.

Needless to say, this is my last Benz. I'm switching to Toyotas.