1982 635csi Euro

I've had this car for a little over a year - got it for a song and have since out in about $3800, which is just about my limit. I do love it though. I just got it back today from a full drive shaft rebuild ($1K) and now sometimes when I put on the brake one of the little dash indicators lights up. It's the one with the Circle with dashed paratheses (as opposed to the un-dashed parentheses on the light to the right of this one) on either side. This has never lit up for me before. Does anyone know what the cra is trying to tell me??!!

Email me directly at marcbenjamin@gmail.com if you can help!

Thanks ;) Marc