These are our most Frequently Asked Questions. Anyway, if you need more info about any of them, please do not hesitate to contact us!

What types of Electrical Wiring Kits for Towbars do exist?

There are two big groups depending on the vehicle type:

1.- Electrical wiring kit without electronic module: made with a wire, socket of 13 or 7 pins and small bits to make the connections to the rear lamps of the vehicle.

2.- Electrical wiring kit with electronic module: as well as the bits of the simple kit, it’s got an electronic circuit to activate the luminous signals of a trailer or caravan without direct power consumption from the rear lamps of the vehicle.

When to choose one type or another?

Simple kits without electronic module are recommended for vehicles with old technology, where the vehicle lights are activated by simple ways, such as relays, and they allow getting the current directly for the trailer or caravan from the rear lights (parallel connection) without vehicle malfunctions.


Kits with electronic module are recommended for modern vehicles, usually from 2000 year and up. These vehicles started using electronic systems to control its luminous signaling without allowing those extra consumptions that occur when there is a straight parallel connection with the trailer lights. By using these new electronic module kits, any extra current will be detected as a Warning Error in the cockpit, so they track any failure in the rear lamps system, which is not designed to supply extra consumption.

What types of Electrical Kits with electronic module does exist?

There are two groups:

1.- Specific kits: designed separately for each maker and model of vehicle, their connections are made by the manufacturer with their own genuine connectors. In the instructions, the disassemblings are indicated more in detail.

2.- Universal electrical kits with module: designed to work in most vehicles. They get the signal controls from the rear lamps, but what it’s more important, avoiding any extra comsumptions. Trailer lights get the current directly from its battery. Of course, they must support the different systems of lighting that each manufacturer designs for his vehicles.

Why is it better to choose a Universal Kit rather than a Specific one?

Main advantage of a specific kit in front of a universal kit is that the specific kit wiring is made of genuine manufacturer connectors for each model of vehicle.


On the contrary, many specific installations require complex disassemblings in order to access to the connection points that the manufacturer has determined. Disassembling of seats and cockpit parts are needed as well, with the consequent long and expensive installation.

Pricing for a specific kit is often higher than for a universal kit, sometimes three times over the universal kit, due to their wiring complexity (different for each maker and model) and their electronic circuit. Each maker and model of vehicle needs its specific kit, so you would need to have in stock every single one on the market.


The advantages of a universal kit are:

– The connections on the vehicle are made in its rear lamps, saving time of assembly.

– Pricing is cheaper in most cases.

– It’s easy to store a small stock of a kit that can be used for most brands and models of vehicles.

– Results and Functions are exactly the same than with a specific kit.

What is the Check-control system?

This is the system incorporated on some vehicles, which checks the status of the lights. Any anomaly, as fused bulbs, extra-consumptions or short-circuits, is detected, warning to the driver. The vehicles with this system require a kit with module to prevent that the electrical system of the trailer or caravan is detected as a failure.

Our universal kit supports vehicles with Check-control.

What is the C2 system?

This is a system incorporated on some electronic kits, which detects failures in the indicator lamps of a trailer or caravan. In some European countries like Germany, Austria and UK the use is mandatory.

Our Universal kit can incorporate this system and gives you warning when detects a failure in the indicator, but also tail and stop lights.

What is a subtitute light system?

This is a security system incorporated on some vehicles. When it detects a bulb fused in the rear lamps, the vehicle by-passes this function to another bulb. For example, if a turn bulb is fused, the car by-passes to another bulb, i.e. fog or tail.
Our universal kits incorporate also this security system that avoids running with turn lights fused on a trailer. In case of failure, the function is by-passed to another bulb.

What is the multiplexed light system?

This is a system incorporated on some vehicles through which two signals are controlled by a single cable (BSI system).

Some vehicles use a single cable to activate the stop and tail lights or the fog and tail lights.

Our universal kit supports vehicles with multiplexed lights.

Switching-off fog lamp option

Sometimes trailers or caravans with shining surfaces can produce an annoying reflection for the driver, when activating the fog light. In an electrical wiring kit with switch-off option, the fog light will only work on the trailer or caravan and will be disconnected on the vehicle. In some countries is compulsory.

Our universal kit can incorporate the fog light switching function.

Why using the parking distance sensor PDC disconnection?

Some vehicles use parking distance sensors PDC to self-detect close obstacles. When a vehicle with trailer or caravan use this system, the towbar might be detected like an obstacle, creating a false warning. That’s the reason why some kits incorporate the possibility of disconnection of these systems.

Our universal kit can incorporate this function upon request.

Others security systems and advantages of our own Universal Kit

Our universal wiring kit incorporates several safety functions and advantages in front of other products:

– Low power consumption assures that the battery won’t be discharged by the kit circuit.

– Activation System of trailer lamps with solid state components.  Mechanical components for these functions, like relays, are not used.

– Protection System against short-circuits on trailer lamps.

– Protection System against possible high tension power supply input and polarity changes.

What happen in cases with lights activation by mass?

There are vehicles with fog light activated by negative, (normally activates by +12V).
For these special cases, some kits don’t support this system and they require to add external components to work.

Others vehicles have all lights with activation by mass (i.e. Jaguar S-Type).


How did we fix this? Our universal kit has a default activation for 12V. But for those special cases of activation by mass, by following several simple steps, the module can be reconfigured and set to allow the activation by negative, i.e. Chrysler Voyager or Jaguar S-Type. If you need more information about this particular case and which are these steps, please contact us.

Choose system with 7 or 13 pin socket

According to the use of towbar, we can choose between socket with 7 or 13 pins:


1.- Socket with 7 pins is normally used for trailers, where the installation is simple and doesn’t need a direct supply +12V.

2.- Socket with 13 pins is used for caravans, where additional lines for the system are required and it also incorporates the backup light function.