Question about parking light switch
 

I tried searching for this and got nothing. This is what I want to do: I wanted to take a couple of blue LEDs and install them behind each speaker grille in my door. But to turn them on, I was hoping to wire them into the switch that turns on your parking/gauge lights. Does anyone know how to do this, and could splicing into those wires pose any threats to the lighting system?

My Randode system taps into the harness under my center console. It required a switch in the dashboard. The parking lights have to be on to turn the randode system on so I think they are linked together. I do not have any lighting problems because of this hook up.

I'm still a little confused. Which harness, exactly? Does anyone have any pics (or maybe just some detailed instructions) where I can find a wire for the power source that's directly connected to that switch in the parking lights lever?