There's a how to and a code chart on SVX-IW.com.
It tells you to drive at a certain speed for a certain amount of time, then stop the car to check it.
Push the passenger seat up as far towards the front of the car as possible. While sitting in the drivers seat...lean over and look near the passenger foot sill...the light will be aiming towards the center of the car... Does that make sense?
Here's kind of a pic...the abs module is in my box here, but would be located under the carpet in the bottom left corner of my pic