Just had a thought, being as I have an extra ABS modulator for my 94 R1100RS. I replaced it back in 06 with a modulator from a K1100RS. Everything mounted up fine, bleed out easily, and my local dealer "initialized" the K1100RS ABS to my R1100RS. Been working great since 06.
Now I wonder if there is a service shop that can test the original ABS modulator from my RS even if it's not installed in the bike?
I was told by another dealer back in 98 that it was "fried" because they could not clear the fault code that was "burned in" because I did too many low-voltage/cold-starts over the many cool seasons here in Wisconsin. At that time I just pulled the ABS relay to turn off the blinking lights. I rode the bike for another eight years w/o ABS, and four of those years were on the same battery the dealer said I should replace.
One thing that did happen back in 98 was a crash that had the bike running, ignition on, laying on it's side, for a mintues after I fell off the bike. I wonder if that scenario had more to do with the fault code issue than the cold starting problem common to the early ABS system.