What should you listen for when checking air lines during an inspection?

When inspecting air lines, listening for air leaks is crucial because even a small leak can significantly impact the performance and safety of the vehicle. Air leaks can indicate problems such as cracked lines, worn fittings, or improperly connected hoses that might fail under pressure. Detecting these leaks early allows for timely repairs, ensuring that the air brake system functions efficiently and safely.

While whistling sounds may suggest a leak, the term "air leaks" more clearly captures the essence of what you're listening for, as leaks can manifest in various sounds, including whistling, but are generally identified as the absence of proper air pressure. Electrical signals and pop sounds are not relevant to the inspection of air lines and do not pertain to the identification of leaks or issues within the air system, thus reinforcing why focusing specifically on air leaks is essential in ensuring vehicle safety and reliability.