How can you test the proper operation of your air brake system?

To ensure the air brake system is functioning properly, conducting a brake efficiency test after building air pressure is essential. This test involves applying the brakes while the vehicle is in a safe and controlled environment to assess how effectively the brakes engage and function.

This procedure allows you to evaluate the responsiveness and performance of the brake system, ensuring it meets safety standards and operates as expected under load. It is crucial for a vehicle’s safe operation, especially for larger vehicles that rely on air brakes for stopping power. Proper air pressure must be established in the system before the test, as insufficient pressure could result in poor braking performance and a misleading assessment of the system’s efficiency.

Other options provided, while related to vehicle maintenance, do not directly assess the air brake system's operation or efficiency. Tire pressure is essential for overall vehicle safety and handling, but it does not specifically test the air brakes. Inspecting vehicle lights is important for visibility and compliance, and monitoring fuel levels is necessary for operation, but neither of these checks provides information on the air brake functionality. Therefore, the focus on conducting a brake efficiency test makes it the correct answer, as it directly evaluates the performance of the air brake system.