“I decided to replace the original car stereo in my Volvo V70 -02 with a new stereo so I will be able to enjoy stuff like mp3, bluetooth and handsfree.
My car has some steering wheel controls for the stereo that I would like to still be able to use. I didn’t expect that to be a problem because there are several adapters on the market that are supposed to be compatible with my car. However I soon found out that they were not! (It seems like the adapters for V70 might have problems with -02 cars due to a slightly different CAN protocol.)
So what to do then? Keep the old stereo? Live a life with non-working buttons? Of course not! If there is no working adapter on the market then we will have to build one!
This instructable can be applied (with some adaptations) to cars where the steering wheel buttons communicates over the CAN bus.”