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Trailer lights are small parts with big consequences. If the lights fail, the trailer fails a WOF, and more importantly you’re towing something other drivers can’t read properly at night or in bad weather. This guide is written for NZ trailer manufacturers who want reliable lighting that keeps customers compliant and coming back.
Start with a complete LED tail-light kit. You get matched lights and cable, the job is repeatable, and you reduce warranty headaches caused by mismatched fittings or brittle wiring.
If the trailer is used for boats or gets regularly wet
Choose sealed LED tail-lights and route wiring to minimise immersion points. Waterproofing matters more than anything else for boat trailers.
If you need a temporary or remove-and-refit setup
A light board makes sense, especially for hire fleets or quick repairs, but it’s not the cleanest long-term solution for new builds.
For manufacturers, the practical take-away is simple: build every trailer so the lighting is robust, securely mounted, and easy for the end user to maintain. Reliability is compliance.
Yes, as long as they operate correctly, are bright, visible, and securely mounted.
What's the difference between IP66 and IP67?
IP66 resists strong water jets and dust. IP67 adds protection for temporary immersion - useful for boat trailer builds.
Should manufacturers use a kit or separate lights?
Kits make builds repeatable and reduce wiring mismatches, which lowers warranty risk.
Why do trailers get WOF fails on lights in summer?
Boat use increases, immersion and corrosion spike, and older wiring gets exposed quickly.
Pick your tail light set up
If you’re building new trailers at scaleStart with a complete LED tail-light kit. You get matched lights and cable, the job is repeatable, and you reduce warranty headaches caused by mismatched fittings or brittle wiring.
If the trailer is used for boats or gets regularly wet
Choose sealed LED tail-lights and route wiring to minimise immersion points. Waterproofing matters more than anything else for boat trailers.
If you need a temporary or remove-and-refit setup
A light board makes sense, especially for hire fleets or quick repairs, but it’s not the cleanest long-term solution for new builds.
NZ legal & WOF basics for trailer lighting
In New Zealand, light trailers must have functioning tail lamps, stop lamps, direction indicators, and a number plate light. Trailers first registered from 1 April 2012 onward require a pair of stop lamps and a pair of indicators at minimum. If any of these don’t work or aren’t visible, the trailer can fail a WOF.For manufacturers, the practical take-away is simple: build every trailer so the lighting is robust, securely mounted, and easy for the end user to maintain. Reliability is compliance.
LED vs incandescent - why most NZ builds are now LED
LED trailer lights have taken over for good reasons. They’re sealed against dust and water, handle vibration better, and draw less power from the tow vehicle. You also get instant full brightness, which improves reaction time for following drivers. Incandescent lights still work, but they’re more likely to blow under vibration or corrode in wet use.Tail-light kits - the simplest way to build repeatable trailers
For manufacturers, kits reduce variables. Every trailer leaves with the same light spacing, the same loom length, and the same mounting approach. That means:- faster builds
- fewer electrical faults later
- easier parts support for your customer base
Boat trailer realities
NZ summer is peak boat-trailer season, and that’s when lighting failures show up. Immersion, salt spray, and repeated launch ramps punish cheap fittings. A properly sealed LED kit and sensible wiring runs are your best defence against the summer WOF rush.Wiring basics
Most lighting faults aren’t the lights themselves - they’re wiring and earths. In production builds:- Keep earth points clean and protected.
- Avoid low dips where water can pool in cable.
- Use secure grommets where wiring passes through steel.
- Provide slack where suspension travel might tug on the loom.
Common faults you can prevent in the build stage
- Intermittent lights - usually a weak earth or plug pin.
- Water inside fittings - seal choice or damage from immersion.
- Broken cable near mounts - loom pulled tight with no service loop.
- Dead indicators - wiring crossed or damaged at flex points.
- Dim lights - corrosion at connectors or undersized cable runs.
Recommended LED tail-light kits for NZ manufacturers
- LED Tail-Light Kit - IP67 (SKU 99595)
Best for boat trailers and any trailer seeing regular wet use. - LED Tail-Light Kit - IP66 (SKU 99594)
Great all-round sealed option for standard light commercial trailers.
Trailer lights FAQ
Do LED trailer lights pass WOF in NZ?Yes, as long as they operate correctly, are bright, visible, and securely mounted.
What's the difference between IP66 and IP67?
IP66 resists strong water jets and dust. IP67 adds protection for temporary immersion - useful for boat trailer builds.
Should manufacturers use a kit or separate lights?
Kits make builds repeatable and reduce wiring mismatches, which lowers warranty risk.
Why do trailers get WOF fails on lights in summer?
Boat use increases, immersion and corrosion spike, and older wiring gets exposed quickly.