Technician A says that most current highway tractors use a 3-line TP valve.Technician B says that a 2-line TP valve will remain OFF (closed)until the trailer air supply dash button is depressed.Who is correct?

Question

Quizplus · Accepted Answer

Technician B is correct because a 2-line TP (trailer protection) valve remains closed until the trailer air supply dash button is depressed, allowing air to flow to the trailer. Technician A is incorrect as most current highway tractors use a 2-line TP valve, not a 3-line.

Technician a Says That Most Current Highway Tractors Use a 3-Line