[viperfan7]

I have a few questions about the BCM and how it actually controls the lights.

For one, is the voltage output 12V, 5V, or 3.3V

And does it control brightness via PWM or by changing the voltage.

I have a bit of a crazy project involving underglow.

Edit: Because I'm an idiot and forgot to mention it, I mean the BCM used by MQB cars

 

[BSM]

What are we talking about? A Phaeton? A Super Beetle?

 

[viperfan7]

Dammit, that would have been smart to include

MQB cars, more specifically the 2017 GTI

 

[BSM]

Ok, which lights?

 

[viperfan7]

Ok, which lights?

Got hold of an oscilloscope, found out the brake lights are 12v PWM at 1kHz.

I'm going to assume the rest will be similar, although the majority will be just a straight on/off

Last thing I'm wondering about are the pins assign to the ambient lights on the BCM, I know they're unused on the golf, but if I can get those working, and they output how I think they do (Brightness, R, G, B) I'll be able to use the existing ambient light menu in the MIB2 to control the underglow via the infotainment system

 

[BSM]

It looks like you’ll need to continue reverse engineering with your o-scope; the workshop manual doesn’t go into much detail at all. There are wiring diagrams and pinouts, that’s about it. There are only 10 hits for “PWM” in the ‘17 GTI manual, and 0 for “RGB”.

 

[viperfan7]

Not surprised, pretty sure its meant for some kind of communication protocol between the BCM and another module sadly, so going to have to forego the MIB2 control of the colors for now, not unless I can get hold of the Ambeint lighting plus module from something like a polo

 

[BSM]

Sounds like a job for a Raspberry Pi or Arduino

 

[viperfan7]

Sounds like a job for a Raspberry Pi or Arduino

That's exactly the plan