Aftermarket gauge lighting 2000 LeSabre?

Im considering adding a few extra gauges to my 2000 LeSabre. I was wondering where I should tap into in order to connect the lighting for the gauges. Radio's a no go; I put an aftermarket one in and theres no illumination wire to my knowledge, and of course the climate control is that stupid plug and play design. If going into the cluster or the light switch, what color are the wires. I cant find a specific diagram anywhere. Any other possible ideas where the lights will go on with the interior lights and not stay on all the time?