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What is a wig wag low-pressure warning device?
- A.A type of turn signal used on trailers
- B.A valve that wiggles when tanks are full
- C.A nickname for the treadle valve
- D.A mechanical arm with a flag that drops into the driver's field of view when air pressure gets too low
Correct answer
D. A mechanical arm with a flag that drops into the driver's field of view when air pressure gets too low
Why
Older vehicles use a wig wag that the driver resets by hand once pressure is restored above the warning point. If it drops on its own while driving, it carries the same meaning as a light and buzzer: stop safely.
Manual topic: Air Brakes - Safety Valve and Low Pressure Warning · From the Air Brakes practice bank (AB-060).