Free CDL Quiz

What is the correct order to connect air lines when coupling a converter dolly to a trailer?

a.Connect the emergency (supply) line first, then the service line
b.Connect the service line first, then the emergency line
c.Connect both at exactly the same time
d.Only the service line needs to be connected

Explanation

When coupling a converter dolly, connect the emergency (supply) air line first. This charges the trailer air tank and releases the emergency brakes. Then connect the service line. This order ensures the trailer brakes are properly supplied with air.

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About the CDL Exam

The CDL (Commercial Driver License) exam tests your knowledge of commercial driving rules, safety procedures, and vehicle operation. You must score 80% or higher to pass the written knowledge test. The exam covers general knowledge, air brakes, combination vehicles, and various endorsements.

This question is from the Double/Triple Endorsement Test #2 section. Practice with more questions from this category to build confidence before taking the official DMV test.

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