I am trying to get my act together enough to build just such a plug in for the CTS-V.
However, what you want is the exact opposite, which is actually simpler.
What you need is to sniff the packet that handshakes the radio and also the radio return line.
The first link I posted does that.
It connects to a USB port and you save files as it captures them.
Then you can "replay" the file.
You don't care what the radio says back, just what commands are sent to unlock it, like wake up and vin verified.
Then you get some hardware that will simulate it.
You could probably do it via USB.
Like I said, the radio repair guys have a canbus generator that does this, so I know it can be done.
I saw one setup that used the serial port and two wires and just a bit of software.
If you want my opinion, it isn't going to be a weekend project.
I would install something else or I would modify the crap out of a stock looking one like I did to my radio.
The link you provided is to a system addition that itself works "standalone" but is connected to a system that is still connected to the bus.
I have heard some good stuff about the Parrot Asteroid unit.
Also, if you search around, there are some radio experts that offer unlocking services/ no vin verify.
Your problem is you need the can bus to be working to control the HVAC.
I would almost bet that the radio is just a display/input for the HVAC, but the control "brain" is not in the radio.
I would like to see what the HVAC control line is, and I bet it is not a simple radio to HVAC control loop.
I have the Camaro, and Both Metra, and Scosche made dash kits that have HVAC controls on it. I would think it would be easier to use one of the Metra kits to control the HVAC and just go with a standard DDIN radio of your choice. You would have to obtain the G8 wiring diagrams, and match up wires to the correct control signals if you used one from a different GM car.
Here is a photo of one I am modifying for fit for my new camaro, where the Metra 18 pin connector plugs directly into the 10 pin HVAC cable that comes from the HVAC module behind the glovebox.
That HVAC control interface controls all HVAC, heated seats, defroster, hazard flasher, and door locks.
It might be "easier" but not as "sexy" IMO
The OEM radio touch screen is what the OP wants.
Although, if one reads the FORD consumer feedback, touch screens are the #1 complaint.
That is actually not a bad Idea. I will keep that controller in mind in case it doesnt work out. I want the look of the original radio but if I can update the toch screen I think that would be even better. I looked into the Parrot screen. That DDIn is a good choice. I may have to start to weigh the options, but for now I need to stick to the plan.
RRay thats not a bad idea. I just looked at that unit and the Scosche unit. I like the Scosche HVAC controls better. But that brings up the same question. Does the Scosche unit connect through the BCM?. I am pretty sure it does but then again I could be wrong. I think that running a DDin and the Scosche unit would be and look better than the stock G8 setup. I could fab a nice mounting plate to mount them with. Heavy Metal any thoughts?
Yeah, the Scosche kit has both buttons and a touchscreen, and looks real nice. I bought my Android head unit with the Metra kit as a package deal, but ended up pulling the Android head unit due to slow boot times and poor shrill sound quality.
Get one of these:
Or do a similar search on ebay for a service manual for your car. This will give you the ins and outs of the system and you can track things down easier. I looked for my truck and it shows the modules and their ID numbers which you need for the CAN scan...
Also realize that everything runs through the CAN now. Your best bet is going to be to mimic the BCM with an Arduino or similar board. I mention the Arduino because there are ODBII shields for it so it should tie in easily. If you can "sniff" the correct codes for the unit you should be able to mimic what you need to talk to the HVAC and Radio. If you can disable the VIN checking all together for the radio it will make things much simpler. My guess is that unless you can reprogram the HVAC and Radio to ignore the CAN bus you will HAVE to mimic the BCM and any other modules they connect to otherwise you will never get them working. The kits mentioned above are only replacing the radio. You still need the HVAC brain to work the rest of it.
If you do this project yourself it could easily get into hundreds if not thousands of hours of just software "stuff" including sniffing and redoing stuff. And you likely need a specialist to reprogram the HVAC and Radio. You might be able to bypass the radio without one but not likely with the HVAC. If you can get the codes as I mentioned you can probably mimic the BCM and get around a specialist as long as they don't pull from any other modules to make important stuff work.
In the end this project will be far more trouble than getting a carpc to do the same job. It will cost you much more in time and money than doing it all with a CarPC. A car PC with a few pieces of hardware and some simple coding and you are all set. With a CarPC you can likely get it up and running within a week or two. It will likely cost more time fabricating the hardware in place than the software tweaks you will need.
I have heard you can get access to the whole GM ODB "code book" but it will cost you a $7000 per year subscription, a signed Non Disclosure agreement and you have to have a business or a good excuse to be able to subscribe. With this you could likely do this project in a very short period of time the way you want it but will still take trial and error.
I am going to email Scosche later and find out if their setup is CANbuss driven or not. I read somewhere about the android setups having problems like that. I also just saw and read about the Parrot system and they are claiming there is no lag and it is super fast with good sound quality. I would have no problems switching over to the Scosche and the Parrot if I knew I could make it work.
One last note on this... I plan to "sniff" the ODB bus in my 03 Avalanche so I can remove the HVAC controls altogether and control everything from an ARM board. I will also be sniffing for things like the headlights, windows and other stuff so I can control them from a computer. I won't be removing anything from my system and I expect it to take dozens if not hundreds of hours of work to pull my codes and I am doing this on a vehicle that I am just tying into and not replacing any components. When done I MAY remove whatever I can that will be controlled via the CAN so I can do it all with a touch screen but I haven't gotten that far.. When done I hope to remove the full HVAC display, the window switches, the lighting switches and whatever other switches I can remove and not seem out of place. But then again I will have touch screens to control this both in the over head console and in the back of the center console for the rear passengers. I expect to spend hundreds of hours tying into this system. I only mention this because my job will likely be MUCH simpler than yours since I already have much of the information. I just need to get an ODB scanner setup and start playing with software.