The service ride control is much like a check engine light and can detect dozens of problems in the system. When the light comes on, a code is set in the body module. A scan tool, such as a Tech II can retrieve the code and point the direction of the cause. From there it is a matter of testing components in the affected area to isolate the exact cause. It could be several things from a loose connection to a bad sensor. The least-expensive way to address the problem is to locate a shop experienced in the system. Many independent shops and some dealerships should be able to help.