2006 silverado illumination/dimmer wire

Does anyone know which wire on my 2006 silverado stereo harness is used for illumination or dimming?  I installed an AVIC-Z1 navigation system, and I want my headlights or dimmer to control the display but can't seem to find this wire. 

from what i can find, there is no illumination wire in that truck.

You can use a relay to invert the polarity on the negative parking light wire: http://www.directwholesale.net/diagrams/diagrams.asp?link=BULLDOG You could also run a wire to tie in anywhere after the parking light relay. There should be a thick brown wire running up to the underhood fuse/relay box that tests 12 volts with the parking lights. If you want, you can remove the parking light relay, and solder your wire directly to the n/o contact (87) of the relay, or go directly to one of the parking lights.My ex once told me I have a perfect face for radio.

Thanks, for now i'll try the junction box near the driver side kick panel and splice the wire.  I'll let you know if it works. 

It worked.  Thanks.  Now that I have this working, I heard there is a way to bypass the AVIC-Z1 navigation by flashing lights three times to watch DVD's while the vehicle is moving (for my passenger).  Has anyone had success with this.  I tried several times with no luck.  Is there a certain time when you flash?

This is illegal and very unsafe and not allowed on these forums, read the rules. Why would anyone want to do this it's very distracting people can't even concentrate while talking on the cell phone much less watching a movie.