Connecting work lights to a trailer for more light whilst working

In this blog you will read:

• Tips for fitting additional work lights around the trailer
• How to determine which work lights are best suited for each situation

Please note: do you use work lights as reversing lights? If so, be sure to check out our special blog post on reversing lights on trailers.

An LED work light on a trailer is essentially an addition to the standard lighting set. The standard lighting set for a trailer consists of: combination rear lights (rear light, brake light, indicator, fog light and a triangular reflector), marker lights and side marker lights.

Choosing the work light - floodlight or spotlight?

When selecting additional work lights, it is important to choose the right light image. After all, each application requires a different light distribution:

Flood beam (wide-beam): Ideal for loading and unloading or for illuminating a large working area around the trailer. Provides a wide, even beam of light.

Spotlight (directional beam): Suitable for jobs where you want to illuminate just one specific spot, such as inspection or precision work.

Good to know: work lights must not be switched on while driving on public roads. Only ECE R23-certified lights may switch on automatically when reversing.

Additional points of interest when choosing a work light

• Light output (lumen): The more lumen, the more powerful the beam. For heavy work in the dark, we recommend at least 1500 lumen.
• Beam pattern: Floodlights for wide light (loading/unloading), spotlights for focused light (specific jobs).
• Housing and IP values: A work light must be able to withstand rough handling. Choose a light with a high IP protection rating (e.g. IP67 or IP69K) for use in wet and dusty environments.
• Approved quality: Choose lights with CE marking and E-approval to ensure they are suitable for use on public roads.

Now that the application is clear, it's all about technology: can the system handle the additional lighting?

Check whether the electrical system is suitable for additional work lights

Before installing additional LED work lights on a trailer, it is vital that you first check whether the existing electrical system can handle this load. This will help prevent interference, overloading or even damage to your vehicle or trailer.

Check the capacity of the lighting system:

• Note the voltage of the system (usually 12V or 24V).
• Check the fuse rating of the existing circuit (e.g. 10A or 15A).
• Calculate the total power consumption of all planned work lights: Formula: Amps = Wattage / Voltage. For example: 30W / 12V = 2.5A per light.
• Compare the consumption with the fuse value, with a margin of ±10%. Do you exceed the capacity? Consider a separate circuit with relay and fuse and connect the lights directly to the battery of the towing vehicle.

Check the trailer’s wiring harness:

• Inspect the cable insulation for damage or ageing.
• Check connectors for oxidation, play or moisture.
• Assess wire thickness: sufficient for current-carrying work lights.
• Check branch lines or extensions for watertightness.
• Are interference or flashing lighting visible? Consider a new or weighted wiring harnesses with waterproof connections.

Truck after installation:

• Check that the work lights burn steadily without flickering
• Check for fault messages on the dashboard (due to canbus)
• Measure voltage drop if necessary (use multimeter)
• Check that the lights respond correctly to switches or vehicle controls
• Truck the lights at full load (all lights on at the same time)

Connecting the work lights to the trailer

There are various ways to connect an LED work light to a trailer. The most common connection methods are explained in more detail below.

Deutsch connector

The Deutsch connector is a commonly used connector for connecting work lights to a trailer and is available in various lengths up to 4 metres. The advantage of a Deutsch connector is that the mounting is easy to integrate into the cabling system compared to other connectors.

Of course, it can happen that an LED work light on your trailer gets damaged. In such cases, replacing the work light is very straightforward. You can simply disconnect the broken work light and replace it with a new LED work light. This is because the LED work lights are fitted with a simple Deutsch connector.

Deutsch connectors are available in various lengths, with the option for branching. This allows you to connect more work lights to your trailer. It is also possible to connect a Deutsch connector to your existing cable using a connection kit.

AMP Superseal connector

The AMP Superseal connector is a waterproof connector that can withstand harsh conditions such as exposure to fuel, oil, salt, etc. These connectors are used in many different industries, such as agriculture, the machinery sector and the car industry, and are therefore ideal for connecting a work light to a trailer.

Please ensure that the IEC529 and DIN40050 connectors are certified to be watertight.

Connection box/distribution box

The connections are linked via a junction box. A junction box can be used as a central unit in which the connections are linked. This is particularly useful when you want to connect work lights to a trailer. A main cable runs from the towing vehicle to the distribution box, from which all the lighting on the trailer is controlled.

Want to know more about the standard connection for a trailer? Then read our article on wiring trailer lighting.

The TRALERT® choice

If you’re looking for a good work light for your trailer, TRALERT® has a number of top-of-the-range options available. These include impact-resistant and extremely robust lights that can withstand rough handling.

Better Light Work Safer!

Interference on the dashboard after adding additional work lights?

You may occasionally see interference appear on the dashboard. When you connect work lights to your trailer, the towing vehicle may fail to detect the LED lighting. This is because the LEDs draw too little power from the towing vehicle, meaning the vehicle fails to detect the lighting. You can read more about this in our article on resolving a ‘ canbus ’ interference.

Tailor-made advice for vehicle manufacturers

Are you involved in the surface mounting, conversion or delivery of trailers and looking for durable, powerful LED work lights? TRALERT® supports vehicle manufacturers with high-quality lighting and smart connection solutions.