Question 20 of 20
Score: 0/0What is the main function of the trailer air supply control (also known as the tractor protection valve control)?
ExplanationThe trailer air supply control sends air to the trailer’s braking system and keeps the brakes on when the trailer is parked or when air pressure is lost.
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Did you know? Always do a tug test after coupling — the exam expects you to confirm the connection.
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