Practice question

You connect the air lines but forget to push in the trailer air supply (red) knob. What happens?

Trailer service brakes work normally
No air reaches the trailer; trailer brakes remain set and the trailer cannot roll freely
Trailer ABS activates
Only the trailer turn signals are disabled

Answer: B — No air reaches the trailer; trailer brakes remain set and the trailer cannot roll freely

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