What should be monitored to ensure the effective operation of vehicle brakes?

Monitoring air pressure is crucial for the effective operation of vehicle brakes, particularly in vehicles equipped with air brake systems. Adequate air pressure ensures that the brake chambers can function properly, allowing the brakes to engage and release as needed. In air brake systems, a specific range of air pressure must be maintained for the brakes to operate effectively; if the pressure drops too low, it can result in brake failure or reduced braking efficacy.

Other factors such as engine temperature, fuel level, and cab lights do not directly influence the braking system's operation. Engine temperature pertains more to the vehicle's engine performance and overall functionality, while fuel level impacts how far the vehicle can travel but does not affect the brake system. Cab lights are related to vehicle visibility and safety but are not relevant to braking efficiency. Thus, ensuring that air pressure is at the correct levels is vital for maintaining safety and performance in any driving situation.