The mystery still remains....
I and a few other 94-97 owners have notorious issues with the ABS light coming on. Along side that, the modulator keeps on making buzzing sounds time to time. Some cases I would get 2 buzz cycles in a matter of 10 minutes.
I dont know what it is that causes it but Ive chose to convert my car to non-ABS. I am in the process of removing the GSR modulator, brake lines, BB, MC and prop valve with ones that are equipped on an RS.