CDL
Doubles and Triples
Practice Test

Question 3 of 3
What is required before you supply air to the air tanks of the second trailer?
Close the shut off valves of both trailers
Open the shut off valves of both trailers
Open the shut off valves of the first trailer and close the shut off valves of the second trailer
Open the shut off valves of the second trailer and close the shut off valves of the first trailer