Is your ABS dash light coming on too, as OlBlueEyes mentioned? Is it intermittent or on all the time? (intermittent [like mine] would suggest connector problems)
I'm having a devil of a time with this currently on my '94. I've been massaging and greasing zillions of connectors (per willwren'* advice) and I seem to be gaining. (It'* weird, though, sometimes it was two steps backwards for every one forward).
I did go into a well-regarded country repair shop for a scan. Amazingly, the mechanic hooked a Snap-on scanner up to just my OBD1.5 socket and read ABS codes!!! Left front hub came up. I had accidentally left the right rear connector open upon starting once and it caught that too. They only charged $20 for the scan. I thought you couldn't read ABS through the OBD connector
Anyway Marv, let us know how you're doing -- this is is an interesting topic.