Q: Your vehicle is fitted with an air-assisted hydraulic braking system. What would warn you that the air compressor is not working?
Correct answer:
The brake pedal feels hard when pressed
Explanation
The air compressor provides high-pressure air that assists operation of the hydraulic brakes. This reduces the amount of pressure you need to apply to the brake pedal. Without this assistance, it's extremely difficult to press the brake pedal down.