Question 85 of 140

Why should you visually confirm the fifth wheel's locking mechanism has fully engaged, rather than assuming it locked from sound alone?

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Visual confirmation is unnecessary once a click is heard
A visual check confirms the jaws are actually closed around the kingpin, since sound alone can be misleading
The locking mechanism cannot be seen from outside the vehicle
Sound is always a completely reliable way to confirm the coupling is fully locked around the kingpin

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Correct answer to question 85 (Combination Vehicles): A visual check confirms the jaws are actually closed around the kingpin, since sound alone can be misleading

Why

Relying only on a sound to confirm coupling can be misleading, so physically checking that the locking jaws are closed around the kingpin gives a more reliable confirmation before driving.

Updated: November 2026

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Why should you visually confirm the fifth wheel's locking mechanism has fully engaged, rather than assuming it locked from sound alone?

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