Maintenance & inspection
What is a lighting check?
A lighting check confirms that all obligatory lamps, indicators and reflectors work and are clean and correctly aimed. Lighting defects are among the most frequently found at the roadside.
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<img src="https://fleetoptix.co.uk/glossary/lights/diagram.svg" alt="lighting check — diagram from FleetOptix" width="880" height="620" loading="lazy">
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<a href="https://fleetoptix.co.uk/glossary/lights">What is a lighting check?</a> — diagram by
<a href="https://fleetoptix.co.uk">FleetOptix</a>
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</figure>They are frequent because they are easy to find and because bulbs fail without warning between checks. That is exactly why the check is daily rather than scheduled.
Dirt is as disabling as a failed bulb, and on winter work a lamp cleaned in the morning can be obscured by afternoon. That is a case for cleaning en route rather than for a different check.
Trailer lighting fails more often than vehicle lighting because of the connection between them, and a trailer coupled at night is the classic case of the check not being done properly.
What goes wrong in practice
- Checked with the ignition off, so nothing is actually illuminated.
- Trailer lighting assumed to work from the unit's dashboard indications.
- Lamp obscured by dirt treated as working because the bulb is intact.