What does a low air warning signal indicate?

A low air warning signal is a critical indicator within a vehicle's air brake system, serving as an alert for the driver. When this signal activates, it signifies that the air pressure in the braking system has decreased to a level that is considered unsafe for optimal braking performance.

Maintaining adequate air pressure is essential for the safe function of air brakes. If the pressure falls below the safe threshold, there is a risk that the brakes may not engage properly, which could compromise the vehicle's stopping ability. This warning system is designed to prompt the driver to take immediate action to address the situation, such as pulling over safely to assess and rectify the air pressure issue before continuing to drive.

The other options pertain to different vehicle issues: overheating brakes would relate to excessive use or friction, worn brake pads are a concern for conventional braking systems, and a malfunctioning air compressor affects the overall air pressure generation. These do not specifically connect to the function indicated by a low air warning signal, which solely denotes insufficient air pressure in the braking system.