Practice question

How should you safely apply the trailer brakes only, for example to test the trailer's emergency function?

With the foot valve
By pulling the red 8-sided trailer air supply knob OUT, which exhausts the supply line and applies the trailer spring brakes
Using only the parking brake
Disconnecting the glad hands

Answer: B — By pulling the red 8-sided trailer air supply knob OUT, which exhausts the supply line and applies the trailer spring brakes

The correct answer is shown above. Try the full quiz for additional practice.