Installing an aux port on a 2007 G6 GT
I am basically looking for the cheapest method to install an aux port with the stock head unit of this car. From what I have read, there are cables/adapters that can plug into the back of the head unit and will then give you access to an aux port to use for various devices. I took my car to the only local car audio store in my town and asked them about it and they said it required a special piece that would need to be ordered and estimated it'd be at least $200 for the install. This seemed steep to me considering Best Buy claims they can install aux ports in any car for $60 (not including the hardware needed).
So my question is, what adapter or cable would I need to do this? I have experience with car audio, but can't for the life of me find an image of the back of a G6's head unit so I can see what ports are there. It also kind of bothers me how difficult it is to access the rear part of the head unit considering you have to remove the glove box of the vehicle among other things.
Can anyone fill me in on exactly what piece I'd need to do this? Also, how would you go about selecting the aux input on the head unit when there is no built in aux port? I know with many head units that include aux inputs, you can just select the aux mode and it will receive input through the port. But since this head unit doesn't include such a port, how would you even select it?
and lastly, anyone happen to have an image of the rear of these head units just so I can have an idea of what I'd be working with?