New 2004 and all 2005 and 2006 GM models already have Automatic Air Bag Deployment Response, Emergency Services and Stolen Vehicle Assistance active when you pick up your new car. The remaining services are usually activated automatically within three to five business days.
Activate your 2004 and older OnStar system by pushing the blue OnStar button in your vehicle. If you hear the recorded message, follow the instructions to speak to an adviser.
If your GM vehicle is preowned, push the blue OnStar button and wait for the adviser to respond to you.
Mention the "Three Months on Us Trial."
The adviser will active your OnStar account, and make sure you do not get billed for the first three months of service.