FYI
All of the 2006 Suzuki Products from Japan (Grand Vitara, XL_7 and Aerio) have an AUX input prewired under the dash. You do not need a CD changer for it to work, it does not require the use of the ce-net.
It Requires a special adaptor cable to active it and tell the stereo something is attached.
Suzuki does not offer this cable.. but.. I have figured out the circuit required to active the input. (only took a few hours on my back under the dash of my Aerio

)
I now have cables available for anyone interested. It has a plug, with the circuit built in to activate the "AUX" option on the deck, and fits into the factory connector under the dash . The cable is about 3.5 feet long and has a 3.5mm male stereo plug on the end
Once the cable is installed, you can press the CD/AUX button and it will cycle between the 2 options and the Display will say "AUX LOW". If you press the Seek up or down, it will change the input gain from "Low"- "MID"- "HI"
It takes less then 5 minutes to install. I have tested this in all models and it works perfectly.
Please e-mail me if you are interested:
tim(dot)mccabe(at)sympatico(dot)ca for details.
Cheers,
Tim