if im right the 2 pink ones are identical and both control the pump. the abs, although tied in with the master is actually seperate. you can unplug the ecu and valve block and your electro-hydraulic master should still operate fine. if it doesnt and still goes hard, the fault may be either the pump, 2 pink relays, or the pressure switch at the master cylinder. if however the pedal and pump assembly work fine with ecu/valve block disconnected, the fault could well be one of the sensors due to dirt ingress, corrosion of wiring, or just a faulty sensor. il try to find the resistances for the sensors for you.