Registering replacement components:

If the OnStar control unit or the OnStar radio frequency modulator unit are replaced, you must call OnStar dealer support by regular telephone and register the new serial number(s).

Synchronizing replacement components:

After registering the new serial numbers with OnStar, you need to synchronize the components. Press and hold the DOT button until the OnStar indicator changes from solid green to solid red, and then back to solid green.