00 cluster in a 99 could be the issue. alot changed 99 into 2000. first thing i would do is make sure there isnt something in the abs ring preventing proper sensor function. if the rings are clean, i would be suspect of the cluster and check the fsm and see what the sensor outputs are supposed to be. if 99 and 00 use the same sensor and output then i would investigate and possibly try a new abs sensor but they arent cheap.