CDL Air Brakes TestAir Brake System PartsMedium
During a test, a driver fully applies the service brakes, and the stop light switch fails to activate the brake lights. What is the immediate safety concern?
- AOver-pressurization of the air system.
- BIncreased risk of rear-end collision.
- CPremature wear of the brake linings.
- DReduced braking power.
Show answer & explanationAnswer & explanation
Correct answer: B. Increased risk of rear-end collision.
The stop light switch activates the brake lights to warn following motorists that the vehicle is slowing or stopping. If it fails, other drivers will not be alerted, significantly increasing the risk of a rear-end collision.
Why the other options are wrong
- A. The stop light switch is not involved in air pressure regulation or safety valve operation.
- C. The switch's failure does not directly impact the physical wear of brake components.
- D. The stop light switch does not affect braking power; it only controls the brake lights.
Stop Light Switch
The stop light switch is a pressure-activated switch in the air brake system that illuminates the vehicle's brake lights when the service brakes are applied.
- Located in the air brake system, often near the foot valve.
- Essential for warning following traffic.
- Failure can lead to safety violations and accidents.
Memory trick: Brake lights tell the tale, or risk a fail.