When connecting LED lighting to your trailer, you may encounter issues where the lighting doesn't work or the LED lights flicker. This can be frustrating, but fortunately, there are multiple solutions for trailer lighting problems. So, you don't need to worry if the LED lighting on your trailer is flickering. In most cases, this is related to the CANBUS system of the towing vehicle. This is a safety system for data transfer between electronic components in a car without the central computer's intervention. LED lighting generally comes with many advantages, but when it comes to connecting it to (older) vehicles, these issues can arise. One of these issues can indeed be a flickering LED lamp. We are happy to explain why the LED lighting on your trailer may not be working and, more importantly, how to resolve these problems.

Problemen verlichting aanhangwagen

Is your trailer ready for LED lighting?

More and more 'old' lighting is being replaced with LED lighting. That's because LED lighting has many advantages over conventional types of lighting such as halogen. For example, halogen lighting loses a lot of energy to heat. This is not the case with LED lighting. LED lighting also lasts longer partly because of this. Furthermore, LED lighting is better able to withstand voltage spikes and is more readily available in many shapes and colors. Do you want more information about the differences between halogen and LED? Then read our blog: Halogen vs LED, the differences.

Because LED lighting loses less energy to heat, it also requires less energy to shine. Due to the lower energy demand, it sometimes happens that the LED lighting is either detected or not detected by the onboard computer. Simply put, too little resistance is provided to the towing vehicle to determine if the lamp is working. This results in an error message on the dashboard or varying resistance notes. The varying resistance note causes the flashing LED lighting. More information on how to solve this will follow later.

Different lighting for trailers

Malfunctions with the lighting are, of course, very inconvenient and not something you want to deal with. Especially since sometimes you can't determine where the error is coming from with the amount of lighting you have on a trailer. There is a lot of lighting available, and some of this lighting is mandatory. Typical mandatory lighting includes license plate lighting, tail lights, retroreflectors, and side marking. This lighting must be constantly on when driving on public roads, except for the mandatory fog light and turn signal, of course. It also depends on the width of your trailer whether clearance lights are also required. You can read the exact rules for the different lighting in our blog about "What are the rules for trailer lighting? - TRALERT®

What causes non-functioning LED lighting?

Newer cars are equipped with the aforementioned 'CANBUS system'. This system ensures that any error messages are clearly communicated to the driver. You can think of it as a tool that simply detects defective parts of a car. The system knows that in the original situation, a certain amount of energy should go to the lighting of the trailer. As mentioned earlier, LED lighting consumes much less energy. The CANBUS system detects that much less energy is going to the lighting and therefore thinks that the lighting does not have enough energy to illuminate. This causes the onboard computer to erroneously think that there is a defect.

led verlichting aanhanger knippert werkt niet flikkerende lampen knipperende lampled verlichting knippert

How do I resolve the issues with my LED lighting?

Problems with the lighting on your trailer are more common (for example, LED lighting flickering), and fortunately, various solutions have been devised for this. Each solution has its own advantages and disadvantages. Not every solution is suitable for every situation. So, pay close attention to your situation and what is most appropriate for it. If you can't figure it out, you can always contact us. Some solutions you can find in the TRALERT® range include the ILS microprocessor, the LED control box, resistors, and the ZS-Canbus wiring unit. Additionally, you can also find plug-and-play Canbus Proof lamps that have been extensively tested on various towing vehicles.

ILS microprocessor

An ILS microprocessor is a very simple solution to the problem with the LED lighting for your trailer. The microprocessor makes a branch of the existing signal. This signal is then sent through the processor without an error message. This ensures that the LED lighting of your trailer simply works again. Keep in mind that every lamp needs an ILS microprocessor. If you don't do this, you'll end up with a flashing LED lamp.

TRALERT® has various microprocessors in its range. The difference lies in the number of pins and the voltage. The TRALERT® ILS microprocessors come in 3-pin and 4-pin versions. Both options are equipped with 12V and 24V connections. So, be sure to check which microprocessor is applicable for you.

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LED control box

Another option is the LED control box. This also ensures that the lighting works properly again. The control box has several advantages over the ILS microprocessor. A major advantage is that you only need one control box. Even if the onboard computer gives multiple error messages, one control box will solve your problem. The control box is very easy to install using plug & play mounting. This saves a lot of costs compared to other options. The control box is widely used for malfunctions with a trailer. An ideal solution for the issues with the LED lighting of your trailer.

TRALERT® offers two different control boxes. Both have a 12V connection. This is because the control box is often used with a trailer. 12V connections are used in most cars. Hence, this is a good match. One control box has a 7-pin connection, and the other has a 12-pin connection. That is the only difference between the two control boxes.


A commonly used way to solve malfunctions is by using resistors. Resistors also ensure that the CANBUS system does not give error messages. Just like with the microprocessors, a resistor is needed for every error message. This makes a resistor a bit more challenging to use compared to the control box. The advantage of resistors is that they work more easily with certain vehicles. The control box is excellent for the trailer but is less likely to be installed in another vehicle. Resistors are easy to use for various vehicles.

TRALERT® offers two different resistors in its range. The difference lies in the voltage. One resistor is suitable for a 12V connection. The other resistor is suitable for a 24V connection. The different resistors are therefore intended for different vehicles.

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The ZS Canbus wiring unit is slightly more complex compared to the other solutions for trailer lighting problems. The wiring unit must be built into the vehicle. Once you have installed the unit, you will never have to worry about an error message again. This is a very good long-term solution.

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Canbus Proof lamps

Another way to prevent issues with your trailer lighting is to use Canbus Proof LED lamps. When the lighting used on a trailer is Canbus Proof, you can be sure that you will not receive any error messages. Prevention is better than cure. A Canbus Proof lamp is the solution when it comes to non-functioning LED lighting. Nothing needs to be built-in or installed. The Canbus Proof lamp gives you the assurance of properly functioning LED lighting.

If you already have the suboptimal functioning lamps at hand, the Canbus Proof lamp is probably not the option for you. In that case, you should opt for one of the other three solutions for trailer lighting problems. If you have yet to purchase the lighting, then you should definitely consider the Canbus Proof lamps.

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Why TRALERT® solutions?

As mentioned earlier, TRALERT® offers a wide range of solutions for trailer lighting problems. There is a suitable solution for every situation. In addition to the extensive range of solutions, TRALERT® also has its own technical service. If you have any questions, you can always contact us. We will help you with personalized solutions for the flashing LED lamp. With personalized advice, you can quickly resolve non-functioning LED lighting. Moreover, TRALERT® has 90% of its products in stock. If you place an order before 3:00 PM, we will ship it the same day. You can expect to receive the product the next day and get the flashing LED lamp working again.