just did radio replacement on my 98, and the steering wheel controls for the audio required the purchase of a box to control the new radio. that doesn't help you...BUT, they did send some wiring diagrams that might.

the instructions came with wiring diagrams for the OEM radio harness. you can look up your vehicle here: Steering Wheel Interface Application Guide and Instructions | iPod Integration for your car and More by Pac-Audio - Connecting you to the future

hope this helps