Which component helps in determining if the air brake system is functioning properly?

The application pressure gauge is crucial for determining whether the air brake system is functioning properly because it displays the amount of air pressure being applied to the brakes. This gauge allows the driver to monitor the pressure levels in the air brake system and ensures that they are within the operational range necessary for effective braking. A proper application of pressure indicates that the brakes are receiving an adequate amount of air, which is essential for safe stopping performance.

A malfunction in the brake system can often be detected if the application pressure gauge shows abnormal readings, such as insufficient pressure or a drop in pressure when the brakes are applied. Therefore, this gauge serves as an essential diagnostic tool for the driver to confirm that the air brakes are working as intended.