Ca-7 Pressure Switch(Es) Operation

Ensure ignition is off. Set ohmmeter to 200-ohm scale. Measure resistance between hydraulic unit Green/Red wire and ground, hydraulic unit Blue/Black wire and ground. Depress brake pedal several times. Connect 12 volts to hydraulic unit Yellow/White, Yellow/Red, and Yellow/Green wires for 30 seconds each (to relieve pressure). Connect 12 volts to hydraulic unit pump motor Red/Yellow wire for 30 seconds (to build pressure).

At low pressure Green/Red and Blue/Black wires should be open circuit. At normal pressure Green/Red wire should be zero ohms and Blue/Black wire should be open circuit. At high pressure Green/Red and Blue/Black wires should be zero ohms. If conditions are correct, repair Black wire to ground. If not correct replace hydraulic control unit.