The status LED on the rear view mirror for my OnStar has been red for over a week now. A couple of years ago, it went red for a day or so then cleared up on its own.
When I called their tech support to run a diagnostic, they said it was a communications failure with the Airbags and, in the event of a crash, might not signal OnStar. I had the airbag recall done last week and the light was red before that.
I stopped in to a local Chevy dealer and they wanted $129 just to diagnose the problem, but the service writer said usually the whole module needs to be replaced and they could do that for $569.
Now that my AWD is turning 11, I'm not sure I want to put that much into the car.