I am assuming this is some sort of error code and yes I swear I did search the forum before posting this.

When My 98 Blazer is in DRIVE there is a solid square light blinking on and off around the D. I have not noticed a particular pattern. Is this an error code or just some weird issue with that panel and light?

 

I also have this problem, and it had continued to turn into a lack of an indicator light while in P R or D occasionally. I don't think it's a very serious issue, the best answer ive gotten is a possible bad ground or connection. if anyone knows if this is something more serious i would be interested to know as well.