Tow-Trust also supplies a wide choice of electrics to complement our towbar range. This includes a full range of both universal and vehicle specific wiring kits. With the developments in vehicle technology over recent years, this page sets about providing you with some detailed information with regards to vehicle specific kits and will hopefully afford you a better understanding of which electrical option you wish to choose next time you purchase or have a towbar fitted.

Since the early 2000's, automotive technology moved rapidly forward in introducing network systems in vehicles which allowed the detection of a trailer. In many cases, not only did the manufacturer design the vehicle to detect the trailer, but created enhanced features within the network, which actually makes it vitally important for the trailer to be 'seen' and not 'hidden' from the towing vehicle. These include some important safety and stability features, along with convenience items such as automatic fog light cut-off and parking sensor deactivation.

Here are some of the related towing systems in a vehicle you may have, which 'need to see' the trailer when it is plugged in:

  • Brake electronics
  • Suspension system (ASS)
  • Engine electronics
  • Engine cooling system
  • Cruise control
  • Parking aids
  • Reversing camera
  • Lane change assistant

Each of the above systems are affected in different ways when a trailer is 'detected'. Vital systems such as engine cooling and brake electronics will function and react differently. TSP ('Trailer Stability Program') is one feature which is being added to more and more vehicles, to help correct the 'snaking' action of a trailer... but with such advanced technology, braking systems have even evolved further by being operated electronically, without the need for hydraulics. Braking has become more controlled with faster braking efficiency when towing and suspension systems can now detect a trailer and allow for a more level towing adjustment when the load is applied on the towing hitch. ACC (Adaptive Cruise Control) systems are meant to 'detect' a trailer in order to help set a greater braking distance between vehicles.

To 'By-pass' all the above safety systems is potentially disastrous as your vehicle is often designed by a manufacturer to behave in a different way as soon as you couple up your trailer or caravan. The manufacturer of the car has either, put a prepared connector in the vehicle which is a CANbus preparation on the network (e.g Audi, Ford, Land Rover, Seat, Skoda, Volvo etc) to accept a specially designed towing module, or has designed the trailer to be 'detected' through connections directly onto the databus (e.g BMW). With these type of connections the vehicle will know when a trailer plug is connected to the socket.

If you accept a 'Universal by-pass' solution, it is most likely the towbar installer will make either crimp or solder connections onto the lighting harness of the vehicle. This can prove to be contrary to what the manufacturer has intended. Therefore, any connections made in this way can also result in potentially restricted warranties. Not only that, but many network vehicles will 'switch off' any supply to a rear lamp on the vehicle should the bulb fail. This will mean, for example, with connections onto a tail lamp wire of the car, should the bulb fail on the car, the system will shut off the supply until the bulb is repaired. This results in not having any active tail lamps functioning on the caravan or trailer!!

In order for your vehicle to 'see' the trailer, it is important you accept a vehicle specific electrical installation.

It is vitally important that towbar installations can no longer, be perceived as a cheap commodity. The towbar is virtually the ONLY accessory which interacts with the vehicle in such detail. NO OTHER accessory affects the way the vehicle behaves or performs particularly in terms of vehicle safety. This must give the towbar installation a higher value other than a 'lump' of metal bolted to the car!

Here are some things to be considered:

  • A towbar has to be THE MOST important accessory in terms of safety
  • A towbar electrical specific vehicle installation is the most interactive of any accessory
  • A towbar installation has become so 'specialised' and is becoming even more so
  • A towbar installation often requires a diagnostic intervention using 'specialist' tools

Whilst the above article clearly sets out the benefits of fitting a vehicle specific electric kit there are still important considerations to be made prior to selecting which electrical option to choose. One such factor is the age of the vehicle and it may be the case that a vehicle specific kit isn't even available for your year of vehicle. Furthermore, as to the necessity of the vehicle specific kit, should your vehicle not have the safety features listed above or optional extras such as reverse park sensors then it is possible to assume that the universal alternative is still safe to use on your vehicle.

As for the consideration of price this will no doubt be a major influence on your decision. In a market where price is very much key it is of course worth considering as you set about getting the best deal. At this point it is important to consider that the best deal may not be the 'cheapest' quote and it is worth enquiring with your fitter what you will receive for your money. If you have paid for a vehicle that has all this modern technology available to it, the cost of the kit to activate these features is a fraction of the cost when you reflect on what you have paid for the vehicle. Furthermore, whilst most of these features are safety features designed to improve your towing experience, can you really put a price on the cost of your safety?

Here at Tow-Trust we offer both universal and vehicle specific options for vehicle towing electrics. The decision of whether to fit a vehicle specific kit or universal by-pass relay should be an informed choice made by the customer following extensive research. Should you require any assistance or information with regards to this topic please do not hesitate to contact our technical department on
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