Towing Electrical Systems

Cars, Motorhomes and Commercial Vehicles are becoming ever more complex, as such it is vital to consider what type of electrical wiring system and sockets you want installed.

Whether towing a large caravan, trailer box, another vehicle or used to support a bike carrier, you will need to fit an electrical socket and wiring kit.


Electrical Sockets

You have 3 options:

  •  single 7 pin (12N)
  •  twin 7 pin (12N & 12S)
  •  Single 13 pin


Wiring Kits

On older vehicles there is a choice between fitting a bypass (universal aftermarket wiring) and vehicle specific electrics. With new vehicles it is essential to fit a manufacturers approved wiring kit. This will ensure the computer systems and safety features are not compromised.  Fitting a bypass or non-specific electrical system could compromise safety and could invalidate the warranty.


Dedicated Wiring Kits

Dedicated wiring kits are the recommended option, more so for modern vehicles, cars, vans and motorhomes, with sophisticated computerised management control systems. Electronic systems with the ability to recognise when a trailer or another vehicle is connected requiring an adjustment to the vehicles’ driving characteristics in terms of weight stability, cornering, braking and safety features. Features such as parking sensors can negatively impact on maneuverability and safety. In these situations, a dedicated wiring system will activate the onboard computer and, when towing, automatically deactivate the parking sensors.


Benefits of a Vehicle Specific (dedicated) Wiring Kit:

• Works seamlessly with onboard computer systems
• Parking aids disabled while towing
• Vehicle warranty protected
• Quality engineered solution
• Designed with reliability and safety in mind

Our guide to choosing the correct socket should help you decide. But if you need further information and advice on best options, then please do not hesitate to contact us.

  • 12N Electrics


    12N Electrics

    Commonly referred to as single 7 pin electrics

    This features a black cover, and is most common and cost effective type of towing socket

    This type of socket controls all rear light functions apart from reverse and is used on most trailers and caravans pre-2008 (but you won’t be able to charge the battery or interior lights of the caravan).

    12N Typical Use

    • Trailers without leisure batteries
    • Boat trailers
    • Cycle carriers
    • As a fly lead-on-clip on cycle carriers
  • 12N and 12S Electrics


    12N and 12S Electrics

    Commonly referred to as a twin electric socket with a 12S socket (grey cover) used in conjunction with the 12N socket when towing caravans, trailer tents, horse boxes and tipper trailers.

    12S electrics has 12 volt permanent power and a switched 12 volt power supply and is used to charge a leisure accessory battery with the charge taken from the towing vehicle charging system via an automatic split charging relay.

    This will ensure that both vehicle and leisure battery remain fully charged and operational even at times of heavy use. The 12S socket also contains a power feed for the reversing lights on the caravan.

    12N and 12S Typical Use

    • Caravans with a leisure battery
    • Trailer tents with a leisure battery
    • Catering trailers with a leisure battery
  • 13-pin Electrics


    13-pin Electrics

    This towing socket  is the newest style of towing socket and replaces the 12N and 12S (Twin electrics). From September 2008 all newly manufactured caravans are fitted with 13 pin plugs that meet ISO11446 international and the U.K. B.S.I. standards.

    You can also have a 13-pin trailer socket (8-pin socket) which is set to replace the 12N socket. This has the added reverse light circuit but does not include a 12 volt circuit which is becoming more common on new type approved trailer.

    The 13-pin socket is waterproof as a twist lock connection is more suitable for detachable tow-bars that have a spring mounting single socket plate that can be folded up behind the bumper to make it invisible.

    13-pin Typical Use

    • Most caravans manufactured after 2008
    • Now starting to be fitted to trailers as standard
    • Combines 12N and 12S


    Choosing The Right Wiring Kit

    When you decide to have a towbar fitted, it is very import to choose the right wiring kit. The right wiring kit will protect the investment you have made in your vehicle, caravan or trailer. S

    Jacques Towbar Services offer two different towbar wiring options – the CANbus system, or Univeral Bypass relay. Below is our handy guide to help you choose the best option for your vehicle.



    vehicle_specific_wiring_loomThe latest in smart technology is the CANbus system. This system facilitates the interaction of different wiring and computer systems, and the detection of a trailer or caravan connection. Computers with advanced sensors and features monitor the safety and stability of both the towed and towing vehicles. They enable the driver to automatically switch off the rear fog lights and parking sensors.

    A Trailer Stability Program will operate automatically when sensors detect changes in operational conditions and caravan or trailer connection:

    • Lane change assistant
    • Brake electronics
    • Adaptive cruise control
    • Suspension system (ASS)
    • Engine electronics
    • Engine cooling system
    • Parking aids
    • Reversing cameras



    • Approved by All Vehicle Manufacturers
    • Vehicle warranty protected
    • Trailer Stability Control and vehicle safety features activated
    • Parking aids and vehicle fog light disabled while towing



    • Higher cost




universal_BypassThis is a very popular option because the towing electrics are separated from the in-car wiring system. This electrical installation is commonly called ‘By-pass electrics’. This system is used to protect the car’s lighting systems from potential damage if the wiring in a trailer should malfunction. It is a tried and tested system in common use.

Due to the complexity of newer vehicles, this option is not recommended by vehicle manufacturers with an existing warranty.



  • Lower price
  • Universal fitment



  • Not approved by manufacturers
  • Vehicle Safety features not activated
  • Trailer Stability Control not activated
  • Parking aids are not disabled while towing
  • Might affect your vehicles warranty

For help or advice about any of our products or services, please contact us.

If you know what you need and you would like a detailed and competitive quote, please use the quote form. We will get back to you speedily and without delay.

Or you can call us on:  0800 772 3213 or 01904 406 321