I have not taken the stock HU out yet, but while looking at the factory harness pinout sticky I see that the harness does not have illumination or dimmer wires since it receives this info through the GM-Lan.

For those of you that have installed aftermarket HUs, what have you tapped into for this?

 

So, no one has installed an aftermarket HU....

I ended up tapping into the 12v switch I ran from the SunRoof fuse. Worked very well.

 

i didnt use the dimer, and the illumination i just paired up with the red power wire, which the power for that came from the fuse box, wiper fuse to be specific

 

Forgive the stupidity, but what is an HU? Also, does anyone know if there are special wires for the sunroof switch? I want to get a switch that allows you to push a button and have it open fully, close fully, or just tilt up. Its a pain to hold it. Just like I want to get two drivers side switches to replace the passenger switch on both sides of the car. Any ideas on the wiring or compatibility would be great.

 

You do realize have your deck in "illumination" dimmed mode all the time with it wired like that, correct?

To the OP, I don't have the illumination wire on my deck hooked to anything right now. The function of that wire is to dim the head units display when it's dark, so the HU is not too bright. Next time I have the dash apart I'm planning on finding a wire that goes hot when the lights are on to connect to the illum. wire of my head unit. I'm thinking the easiest way to find a wire is to tap off either a headlight or taillight wire after testing it.

 

HU is shortform for Head Unit (cd,dvd,am/fm receiver)