Mercedes HID Xenon ballast or ignitor may fail and cause one of the headlight to not work. In this guide, you will find instructiosn on how to replace Mercedes Xenon HID Igniter.
First, you need to confirm that the HID bulb is not burned out. Burned out HID bulb is a very common problem. To learn how to change Mercedes HID bulb follow this guide.
On older Mercedes-Benz models, the ballast and ignitor were mounted under the headlight. Typically this required that you either remove the headlight or loosen the front bumper to access the ballast. On newer Mercedes models, the ignitor is mounted right on the back of the HID bulb.
Common signs of a bad Mercedes ignitor is that one of the headlights are out. When the ignitor starts to fail, it will work randomly. If the HID bulb is burned it will never come back on or work randomly once it fails.
First, check the low beam fuse. Mercedes uses a fuse for each of the headlights. Therefore you have a left and right headlight fuses.
If the fuses check out and are not burned, you need to check the ignitor.
Swap the ignitor with the other side.