This just happened to me yesterday... I just started my search and saw this at the top of the list and had to comment.
I'm gonna search around and see if this has already been answered before. If I find something, I'll try to remember to copy a link into this post.
**Edit - I searched around and didn't find anything on this...
As an FYI - the car's an 06 G6 V6 Sedan and the display which shows fuel economy/etc, temperature and radio is blank... Assuming, like you said that it's some sort of light, but I'm not sure. I'll look into it tonight and see if I can figure anything out with it.