CDL drivers must be able to identify and operate stop light switches in all types of vehicles they operate. You can take a look at our content about stop light switch cdl that we have compiled from all of sources.
A stop light switch is a switch that is activated when the brake pedal is depressed. This switch sends a signal to the brake lights, which then illuminate to warn other drivers that the vehicle is slowing down or stopping.
Site:
https://www.driving-tests.org/driving-safety/what-is-a-stop-light-switch/