I believe you've found the root cause. Just seems very much like circuitry and signaling issues. Meanwhile dealers and garages alike are ripping 100 series owners new ones.
My LC is indicating the following ABS Codes:
1. C0278 - Open or Short in circuit in ABS solenoid relay
2. C1252 - Hyd Boost Pump Motor Malfunction
3. C1253 - Hyd Boost Pump Motor Relay Malfunction
4. C1254 - Pressure Switch Malfunction
I am having troubling accepting these are not electrical...
Is this THE solution thread for all things 1999-00 "ABS Light" AND "aural tone" _AND "No pressure at brake pedal" AND "No brakes" ?
I really do not have 2-4K for someone to rip me a new one.....