I've got the 2005 service manuals, and there isn't really one schematic of just the head unit connections. It's kinda spread out through some sections as I recall. Can you post or email me the one you have and I can check it out for differences? I could also scan the connector pinouts, if that helps (NOTE that this will the pinout of the connector in the car, not the radio itself)I've swapped out a single-CD with a 6CD in a 2005, with no wiring changes, if that helps.(IM me if you need my email)
2005 Platinum Base ManualSide & Curtain AirbagsABSPower PackageTinted Windows"Mods": 'old-style' center armrest, center +12v, wheelskins leather steering wheel, AC/Recirc blue backlight, beeps on keyless entry, dome light switch, AC insulation, PCD10 10-disc CD/MP3 changer, AAI-GM12 AUX audio input, K&N filter, "shark fin" antenna.