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1. What color is the service air line on a combination vehicle?
2. What color is the emergency (supply) air line on a combination vehicle?
3. At what PSI range does the tractor protection valve automatically close?
4. What is the purpose of the tractor protection valve?
5. What knob color is the trailer air supply control?
6. Why should the trailer hand valve (trolley valve) NOT be used for parking?
7. What should you do immediately after locking the kingpin into the fifth wheel during coupling?
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