Ignition wire in the head unit area?
 

“head unit”, not “hehe unit”. For some reason I can’t edit the typo in the title.

Hello, I have a 2006 L322 4.2 V8 Supercharged.
Originally it had a Logic7 amp with the touchscreen, connected to the amplifier in the rear using fibre optic MOST bus. I’m trying to wire up a new head unit. The fibre optic bypass is already solved, this is not about it.

I need an ignition wire (+12V available when the key is turned in the ignition) available as close to the location of the original head unit as possible. I can’t find any wiring diagrams for these pieces. Any idea where I can hook into?

My last resort will be to find the wires powering vanity lights, they have to go through A pillars somewhere, I think, and hook into these - but they are on a 5A fuse. My new radio is rated at 15A max consumption so I’d have to upgrade the fuse, which is not something I feel really comfortable with. Maybe something closer? Maybe I can hook directly into ignition barrel, but I’m not sure how to get there. Will appreciate any suggestions.