If you are losing speedo as well as have the light, it can easily be the relay that DJ mentioned. It COULD be the ABS module, but failure of the Traction Control relay (or it's two fuses) to provide power to the ABS module will give you the same symptom. This is all a sign the ABS module is not working, question is, is the module failing or is power to the module failing?

Since it comes and goes, I'd bet the Traction Control relay contacts are pitted and filthy (common) or the armature is sticking due to age.
Send the RCM to DJ and let him go over it, like so many of the rest of us have.