[scubasteve2365]

I don't have bluetooth in my car and do not want to spend the amount of cash required to retrofit it anyway, and even if I did, it wouldn't give me A2DP bluetooth streaming.

Instead I have an aftermarket bluetooth module for both handsfree and A2DP, which has the ability to answer calls and skip tracks and I'd like to tap into the steering wheel control buttons and use them to control this aftermarket bluetooth product.

I tried searching but didn't find much, what I did find stated that there is only one pin that leaves the steering column, of which each button on the steering wheel correlates to a different voltage level on this pin. While I obviously would like discrete button access, this will also work. I'm an electrical engineer and I can work with varied voltages that would switch a set of dry contacts.

What I'd like to know is where the steering wheel wiring goes? At any point are there switched outputs corresponding to each button? Any info would be great.

[gmfm]

The steering wheel buttons appear to communicate on the CAN bus. It looks like there are some interfaces available, such as this http://www.cellularaccessory.com/sw101.html
If you're really feeling adventurous I'm sure you can do some microcontroller programming and intercept the messages from the CAN bus yourself.

[samwoo2go]

parrot makes modules that hook their bluetooth kits to steering wheel buttons, actually the pic on their website for that module is a BMW. I dunno if it will work with non parrot bt kits tho