If you look here http://www.stevieg.org/carpc you should find I did the same thing a few years ago, with software available for download if it's any use
Hello,I am from Turkey.
I have carpc project on my car.I install and am using it for two weeks.
I did not use to my cars radio control on steerig whell.I did a converter for this.I hope it will be helpfull this forum users.
I used to multimedia keyboard board staff