Practice question

For the Washington CDL Air Brakes knowledge test, what is the trailer protection valve, and where is it located?

  1. A check valve on the tractor that automatically isolates the tractor air supply from the trailer if a trailer line breaks
  2. On the trailer axle
  3. Inside the cab heater
  4. On the drive shaft

Answer: A — A check valve on the tractor that automatically isolates the tractor air supply from the trailer if a trailer line breaks

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