I've searched and come across many conflicting posts. Which is the correct wire to tap for the control unit's illumination and how does it behave when tapped to the said wire?

here... the end.

http://forums.nasioc.com/forums/showpost.php?p=7558709&postcount=17

I was looking for it to dim with the gauge cluster but I hooked it up like that and it works just fine for now. Thanks!