So I don't think it's required (s5, n/a), but there is an orange wire for the AFC that I don't know what it goes to. I've read the wiring diagram cover to cover, as well as searched this site, and still don't know exactly what it does.
The wire is labeled: "To illumination power for audio, etc."
Orange wire: Illumination power.

Any help is much appreciated. Thanks.

 

It's for dimming the SAFC when you turn on the lights. Yes, you do not need it. I have it hooked up to the illumination wire for the stereo since I don't have a stero anymore. Basically your SAFC will dimm when you turn on your lights... so you can see better at night and not get blinded by the bring SAFC... haha Does this answer your question?

 

Yes it does, finally, thank you!
I'm just going to keep it hidden in the glove box anyway.