It's an easy job, as long as you're happy to split the headlight...
You can then remove the black plastic shroud behind the lens. I tried to glue a flexible led strip to it, but had to make some small holes and cable tie it...
All I did then was put a tiny hole at the back of the headlight, take the wires out there to the sidelights unit - just watch the polarity, they'll only work one way round (but won't blow up the other way

)
I'm gonna tidy it up with some proper plugs, and I have SMD (super bright) LEDs to experiment with on a spare shroud.....
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Audi, Vide, Tace
aurantiacus tempestas es ocius
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