Thanks in advance for any help you can provide. I have a 2012 E550 AWD. The right head lamp went out a couple of weeks back. I replaced the lamp and it worked for a day and went out. I also swapped the module fuses and the head lamps remained the same. I've read about replacing the head lamp control module, but wanted to ask this forum if there are other steps that could be accomplished before that. Thank you, Eric

 

Are these HID or halogens? Given that it is a 550, I assume they're HIDs.

In the case of HIDs always swap the bulbs from side to side first. That way you know if the bulb itself is the culprit. If the problem does not follow the bulb, the next most likely failure is the ballast.

 

Thanks for the quick reply. Bulbs are HID. Does anyone have a link to some instructions to replace the ballast? Thanks again. Eric