In this blog, you will read:
- Causes of Flickering or Non-Working LED Lights: Learn about the impact of the CANBUS system and other common issues that may arise when connecting LED lights to your trailer.
- Oplossingen voor verlichting problemenDiscover effective solutions such as using ILS microprocessors, LED control boxes, resistors, and CANBUS-proof lights to quickly and efficiently restore your lighting.
The Situation: Trailer LED Lights Flickering/Flashing
When connecting LED lights to your trailer, you might encounter issues where the lights don't work or the LED lights flicker. This is inconvenient, but don’t worry as there are several solutions for trailer lighting problems.
In most cases, this is due to the CANBUS system of the towing vehicle.
This is a safety system for data transfer between electronic components in a vehicle, without the intervention of the central computer.
LED lighting generally offers many advantages. However, when it comes to connecting to (older) vehicles, such problems can sometimes occur.
One of these problems could be a flickering LED lamp. We’ll explain how the LED lighting on your trailer might not be working. More importantly, we’ll show you how to solve the issues.

Identifying the Problem
Issues with lighting are of course very inconvenient. Sometimes it can be quite a puzzle to determine where the fault originates, especially since larger trailers often have a lot of lighting. This includes mandatory lighting such as license plate lights and LED rear lights, as well as side markers.
Welke regels er precies gelden kunt u lezen in onze blog over “What are the rules for trailer lighting? - TRALERT®“
Is your trailer suitable for LED lighting?
The trailer or vehicle may have originally been equipped with halogen lighting instead of LED. LED lighting has different electrical properties than traditional halogen, such as lower resistance. If the trailer is not equipped to handle this lower resistance, it can lead to issues such as flickering or non-functioning lights.
Because LED lighting loses less energy to heat, it also requires less energy to shine. Due to the lower energy demand, it can happen that the LED lighting is sometimes detected and sometimes not detected by the onboard computer. No worries, there are solutions for this.
Want to learn more about the differences between halogen and LED? Read our blog: Halogen vs LED, the differences.
CAN BUS Compatible LED bulbs
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.

Solutions for flickering LED lights
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.
An ILS microprocessor ensures stable signal transmission and prevents flickering by creating a stable resistance. Ideal for vehicles with a 12V or 24V system.
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.
With an LED control box, you have a universal solution for flickering lights. Easy to install and saves time and costs by minimizing error messages.
Resistors
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.
ZS-Canbus
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.
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.
TRALERT® Canbus solutions
As mentioned earlier, TRALERT® offers many different solutions for trailer lighting issues. There is a good solution for every situation. In addition to the wide range of solutions, TRALERT® also has its own technical service. If you have any questions, you can always get in touch. We will help you with personalized solutions for flickering LED lights.
Questions and answers:
Why do trailer lights flicker?
- This is often due to incompatibility with your vehicle's CANBUS system. This system detects an unusual resistance caused by LED lighting. The CANBUS system sometimes interprets this low resistance as a fault, which leads to flickering of the lights.
- Another common cause is a poor connection or faulty wiring in the lighting system.
Advice: Check if there are any error messages displayed on your vehicle's dashboard indicating problems with the lighting. Modern vehicles with CANBUS systems often show error messages when there are issues with the lighting.
If it is a CANBUS issue, you can check whether the lights on the trailer are "CANBUS Proof" or "CANBUS Compatible." These lights are designed to work well with modern CANBUS systems and should cause fewer problems.
You can then consider replacing the lighting with CANBUS-proof lights or trying to address the issue with a CANBUS control box.
What is the cause of the trailer lights going out?
- If the lights on your trailer go out, it can be caused by several factors. A common cause is an issue with the power supply or a faulty bulb. With LED lighting, incompatibility with the CANBUS system can lead to the lights turning off because the system detects a fault due to the low resistance of LED bulbs. A poor connection or damaged wiring can also cause the lights to go out.