High beam assist on Mercedes C-Class via CAN

Hello everyone.
I have a question.
I would like to control the high beam activation on a Mercedes W205 (C-Class, T-model, year 2019) via CAN bus. My attempts so far have only been partially successful. I've found the relevant signals on the wsgn/gn bus, which is the same as the one directly at the headlight. There are two IDs that change when the high beam is activated. If I enter these commands into the computer, at most the fan in the headlight turns on briefly.
Does anyone have a tip for me? Am I on the right bus, or are there other ways to feed in [data/information/power, etc.]?
Thank you in advance. Best regards.

Hi,

If you simply feed the signals into the bus, please remember that the car is always sending a "horn off" signal. If you briefly send a "horn on" signal in between, the original "off" command will still remain. Try just sending your fake signal to the corresponding control unit (by disconnecting the cable).

Best regards, Rainer.

Hello.
First of all, thank you for the tip. I've looked into the topic again. I found the CAN commands for turning the high beams on/off on two different buses. It seems to be true that the signals for "on" and "off" are constantly repeated by the car. This is good for monitoring, but not for controlling. A short, intermittent signal in between won't do anything. The only remaining option would be to filter the headlight protocols and inject our own, but that would be far beyond the scope of the project. For vehicles like the Sprinter and V-Class, Mercedes offers original modules for a wide variety of input and output functions, but unfortunately, this is not available for passenger cars.
Unfortunately, it's not possible to operate the headlight independently. If you disconnect it from the car's CAN bus, it goes into emergency mode (low beam on) and still doesn't respond to the input signals I'm sending. In addition, the turn signals no longer work, and the daytime running lights are also not functioning.
That probably settles it, unless someone has a revolutionary idea.
Best regards, Thomas.

For many functions, there is still the possibility to send an actuator diagnosis via the diagnostic CAN.
You could try addressing the high beam issue without having to modify the actual dataset.

It might be possible, but I'm not aware of any affordable, small module that can be permanently installed in the vehicle's diagnostic port and intermittently turn the high beams on and off as needed. Do you have any ideas?

For this, you could use, for example, an Arduino Nano with an MCP-CAN board, but you'll need to write the software yourself.
I would simply have the diagnostic tester log the requirement and then incorporate it into the program.