Electrical Circuit

The ABS electrical circuit is protected by two 30-amp fuses, which receive direct battery feeds. The system is switched on by the ignition switch via the ECU.

Electronic Control Unit The ECU processes information from the wheel speed sensors and the various switches for system operation, control, and warnings.

Main Relay The main relay provides the power for system operation. The control circuit is switched by the ECU from an ignition ON signal.

Pump Relay The pump relay provides remote pump switching. The control circuit is ignition fed (via the load relay) and is switched by the pump contacts in the combined pressure switch.


Reservoir The reservoir contains three fluid level operated reed switches. Two "normally open" switches light the BRAKE FAILURE warning if the level drops too low. The third "normally closed" switch signals the ECU if the level drops below a minimum level for full ABS operation. In this case, the ECU switches off the front wheel ABS and lights the ABS warning.


Combined Pressure Switch The combined pressure switch contains three pressure-operated switches. The two "normally closed" switches open when normal operating pressure is reached, switching off the pump and the BRAKE FAILURE warning. The third "normally open" switch closes if the system pressure falls too low and signals the ECU, which lights the ABS warning.


Main Switch The main switch activates the main valve on signal from the ECU.

Diagnostic Socket The diagnostic socket is provided for conducting system self tests.