range? My car broke down earlier this evening and I had no cell phone service to call anyone. I drive 2 hours a day, 5 days a week in areas that don't have cell towers. Ho will this work with OnStar. I will no doubt.. feel safer.
I guess I wasn't clear. I don't have OnStar. But it scared me enough today, that i might consider getting it, if it will work out of cell phone range

Onstar is supposed to work the same way an onboard GPS system does - using satellites, so that should work in more places than a cell phone. It's still limited because it needs to be able to locate satellites overhead. If you're in a flat open area or top of a mountain, you should have no problem, but you may inside a tunnel, or in a narrow valley unless there are satellites directly overhead.

All you need to do is push the button and a friendly on star rep will be more than happy to answer all your questions.

How You Stay Connected
Contact OnStar using the three-button system
Establish direct voice contact with an OnStar Advisor using the built-in microphone, cellular antenna in your vehicle, and cellular network
An Advisor can pinpoint your location using GPS technology. (Based on model availability.)
If your air bag deploys, a message is sent to the OnStar module in your vehicle. The OnStar module then contacts the OnStar Call Center.* (Based on model availability.)
OnStar module connects vehicle computer to OnStar via cellular antenna
Cellular antenna connects vehicle through cellular network
Or you can go here.http://www.onstar.com/us_english/jsp/coverage_map.jsp