Practice question

What is the role of the wig-wag (mechanical low-pressure warning device) in some older trucks?

  1. A coupling for trailer lines
  2. A spring-loaded mechanical arm that drops into the driver's view when air pressure drops below about 60 psi
  3. A type of slack adjuster
  4. A type of brake drum

Answer: B — A spring-loaded mechanical arm that drops into the driver's view when air pressure drops below about 60 psi

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