interior illumination wire?

hi all
just wanted to know i have all my stereo wires together i know where to put them but for one its a blue and red looked in the haynes manual but its not there i think its for the interior illumination so ive been told i connected it to a live and my front lights came on and so did the stereo but its not stated in the haynes?

I have the same problem and Hope to get an answer soon so If you get one first I'd appreciate it.