The switches on the wheel are a multiplexed signal. The bcm is looking for different voltage drops as each switch is pressed. The fact that none of the switches works leads me to believe that you have: A bad ground, no power to the switches or a radio that can't be controlled by the switches. You could put the van on a bcm capable scanner and look at the voltages the bcm is seeing as you press the switches. No voltage (blown fuse, bad ground, bad power lead), voltage changes but the stereo doesn't react (sereo not interfaced properly with steering wheel controls). I guess it's possible the stereo was replaced and wasn't plugged in properly? Good luck. Just as an FYI, I have the steering wheel stereo controls on my van and have never used them.