Which of the following is a reason for a horn to fail inspection?

A horn can fail inspection due to a malfunctioning switch because the switch is essential for the operation of the horn. If the switch does not function correctly, the horn cannot be activated, making it ineffective as a safety feature. A well-functioning horn is crucial for alerting other drivers and pedestrians. Therefore, ensuring that the switch operates properly is a key aspect of safety inspection.

In contrast, while a horn being silent at all distances also indicates a failure, the malfunctioning switch highlights the specific component that could be repaired or adjusted to restore functionality. Similarly, a horn that is too loud might be a nuisance but does not inherently mean that the horn is malfunctioning; it may still operate as designed. The requirement for the horn to work correctly underlines the importance of its operation but does not pinpoint the specific issue like the malfunctioning switch does.