02 DTS Dash Light Problem

I know I've seen this on here some where but can't seem to find it but I have an 02 DTS with factory Navigation and my dash and steering wheel lights work when they want to. I remember seeing something on here about the factory Nav radio have it's own power supply and some wire needs to be cut for it to work propeerly but can't seem to find it anywhere. aAny help or suggestions are greatly appreciate. Thanks