Left low beam not working

Hi,

Where did they test and not find any power? At the bulb itself? I attached how the low beams work and the actual light is controlled by by the control unit which gets power from the Front control module. So we need to find out if the control module is getting power and if so, then that is most likely the issue. However, these are not things we want to guess at when there was an accident involved. We need to test it and see where we have power and where we don't. I also included the wiring diagram that shows circuit 56 that is talked about in the description of the system.

If you don't feel comfortable doing these tests, then we may need to find a shop that is familiar with these cars. Unfortunately, everything is electronic on them and can be confusing if you are not familiar with them.

If you are going to perform this then here is a guide that will help with wiring testing:

https://www.2carpros.com/articles/how-to-check-wiring

Sorry I don't have just an easy answer for you but unfortunately not much is easy on a Mercedes.

Hi there. Thank you for the response. The mechanic was able to see that there was no power going to the plug that connects directly to the bulb (I think he tried the bulb from the right side and it didn’t turn on either). He actually suggested the module that is directly beneath that bulb as well. Also, Ever since the accident I have noticed that the drivers side headlight assembly fills with condensation. It’s as if the seal is broken. If it is a module problem (from what I’ve read online it could be that it is corroded from the moisture), would that be something that I could just order and sort of swap out on my own? I’m hoping it wouldn’t need any kind of special programming or anything? The electrical side of things is kind of over my head. Thanks again, much appreciated!

First, the assembly filling with water is because the seal is broken. Unfortunately, the only way to fix it is to replace the assembly.

As for replacing the module, it is not too complicated but does require an alignment check after you are finished. If they didn't confirm that there is voltage coming into the module then I wouldn't want to guess.

Let me know if you have questions. Thanks

Well, my low beam isn’t working in my Mercedes. I have D1s bi xenon bulbs but the problem is in the control module and plug on the actually headlight assembly (they are corroded from an electrical short). Anyways I ordered a new module but was sent one that is a little bit too small but supposedly compatible with my vehicle. I am guessing I was sent the module for a halogen light. If so, does that mean I could order headlight assembly that are meant for halogen bulbs and just put those in and use my new modules? Thank you!

Well the issue is the non Xenon lamps do not have a control module. So you may be been sent a part for a different vehicle. Do you have the part number on the receipt and does it match the part number on the actual part (assuming it has one on it)? If it does not then you will have to return it and have them send you the correct part. If it does match, let me know the number and I can try to look it up and see if it will work.

The first diagram is for your vehicle and the second shows the non Xenon lamps and you will see there is no control module.

Would it be possible to downgrade my hid lights to halogen? Just buy two new assemblies that are for the halogen bulbs? If so what would that entail? Would I also have to buy new wiring harnesses or a conversion kit or something? Thank you!

It is possible but you are correct that it would take a new harness or at least re-wiring the one in there. Take a look at the difference in wiring that I circled. The first one is your vehicle and the second is the halogen bulbs.