Note: this article describes the regulations in force in Poland. Requirements in other countries may differ – check your local rules.
How many functions does a rear lamp need
The most popular arrangement is three functions in one housing: position lamp, stop lamp and direction indicator. Such a lamp is sufficient for most small and larger trailers. If the trailer is also to have a reversing lamp, a rear fog lamp or registration plate lighting, choose a lamp with more functions or add separate lamps. Which lights are mandatory is described in the article Trailer lighting – regulations, and where to mount them in the guide How to position the lights on a trailer.
Why LED rather than bulbs
- Faster stop lamp response – LEDs do not need time to warm up, so the stop lamp lights up instantly.
- Shock resistance – an LED has no filament that could break from vibration. This matters on a trailer that travels on uneven roads and fields.
- Low power consumption – e.g. in the LZD 2246 lamp the position lamp draws 0.2 W (12 V) and the stop lamp 1.6 W (12 V).
- Sealed housings – many LED lamps have an IP68 rating, so they cope well with mud, water and trailer washing.
What to look for when choosing
12 V or 24 V
A trailer for a passenger car usually runs on a 12 V system, while a trailer behind a truck often runs on 24 V. Most LED lamps in our range have a 12/24 V supply, so they suit both.
Mounting side
Some lamps are universal – they can be fitted on the left or right side (e.g. EMA LZD 2540). Others come in pairs: left and right, e.g. when the registration plate lamp is only in one of them.
Triangular reflector
A trailer must have triangular reflectors at the rear. The easiest option is a lamp with a built-in triangle, e.g. LZD 852 – LED position, stop and indicator, 12/24 V. You can also fit separate triangles from the Reflectors category.
Registration plate lighting
Some lamps have it built in, e.g. EMA LZD 2544 (left version, 12/24 V, IP68). Otherwise, choose a separate lamp from the Registration plate lighting category.
Dimensions and hole spacing
When replacing old lamps, check the dimensions and mounting hole spacing – we give them in the technical data of each lamp. Where space is tight, low-profile lamps work well, e.g. the LZD 2246 with a height of 27 mm, or the compact LZD 2100 (105 x 97 mm, mounted with two M5 bolts).
Indicator flashes too fast after switching to LED
After replacing bulb lamps with LED, the indicator may flash faster than usual – this is the so-called lamp failure error, because an LED lamp draws much less current than a bulb. The solution is a resistor mounted in parallel with the lamp, between the positive and ground wires, bolted to a flat metal surface:
- REZ 2458 – for 12 V systems, 10 Ω, with an aluminium heat sink,
- REZ 2459 – for 24 V systems, 33 Ω, with an aluminium heat sink.
If you prefer to stay with bulbs for the stop lamp and indicator, choose a hybrid lamp, e.g. LZD 2011 – LED position lamp, with the stop lamp and indicator on P21W bulbs.
Magnetic sets – when the trailer has no wiring of its own
For temporary lighting of a trailer, a towed vehicle or a load protruding beyond the vehicle outline, a set of two magnetic lamps does the job, with no drilling or rewiring:
- ZPR 2128 – position, stop and indicator, 12 m cable with a 7-pin plug, without plate lighting,
- ZPR 2132 – the same with registration plate lighting.
Type approval
A lamp fitted to a trailer used on public roads should be type-approved – you will find this information in the technical data of each lamp.
Lamps for agricultural trailers and the other requirements for tractor combinations are described in the articles Lighting and marking of agricultural vehicles, machines and trailers and Tractor lighting.
You will find all models in the LED rear combination lamps category, and the full range of rear lamps in the Rear combination lamps category.