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Cars are becoming ever more complex and it is vital to consider how your towbar electrics are installed…

Whether you are using your towbar to tow a large caravan, or simply just to support a bike carrier, you will need some electrics with your towbar.

The days of simply wiring a socket straight in to your existing vehicle lights, apart from the odd exception, are now long gone. Modern day vehicles are now manufactured with a host of technical features and in particular the introduction of CANbus into vehicles makes wiring a far more complicated procedure. Within a modern car are components (such as ECU's) that without care can be easily damaged and extremely expensive to replace, at best the vehicle may log a fault code, for which most dealers will charge you £70 or more to remove.

Therefore wiring a trailer or caravan is no longer a practice for the novice, just ask yourself the questions "Do I have full, practical knowledge of Ohms Law, do I really understand modern day auto electrics?" and if either answer is no, the advice is to stay well away​!

A simple example.....wrong gauge cable may cause resistance, resistance may cause heat, heat may cause.........fire!

There are various options available to wire your new towbar as seen below but if you have any questions please don't hesitate to contact us.

Single Electrics, which can also be known as 12(N) provide power to lights, indicators, brakes etc on a trailer through a 7 pin socket. This wiring will give you all you need to tow a trailer legally.

You can also tow a caravan perfectly within the law with single electrics, but you won't have power to interior appliances, such as a fridge or have the ability to charge the caravans leisure batteries' while driving.

Even if your only intent is to use the towbar to carry cycles it is still recommended to install this wiring so that you are able to power a light board.

Twin Electrics, also known as 12(S) are fitted as an additional 7 pin socket to single electrics.

​If your caravan needs to power a fridge, run interior lighting or charge batteries while towing, then you'll need this extra socket.

However, this only applies to caravans manufactured prior to 2008, as in the UK after this date the socket was replaced by the new 13 pin socket which gives full functionality from a single socket (shown right).

13 Pin Electrics, is simply a combination of 12(N) and 12(S) in one single socket.

This has been the standard in most EU countries for some time and is now replacing the traditional 7 pin sockets in the UK.

The 13 pin socket may also be used where space is limited behind a bumper, particularly when fitting a detachable towball.

Cable adapters are available to convert twin electrics to 13 pin should you require.

And now your choice of electrics.........

There are two available options when wiring your towbar, either universal after market or vehicle specific​​. Vehicle specific, often referred to as dedicated wiring can be a more expensive option, but has significant benefits to justify the extra cost. Please note that with some vehicles Towbars Wales WILL ONLY fit a dedicated wiring loom.

As already mentioned, the technology in your vehicle is becoming increasingly complex, it is therefore absolutely vital to choose how your towbar is wired.

Universal wiring is appropriate for use in a majority of vehicle types although they are not designed with any specific make in mind and will be incompatible with more complicated vehicle electrical systems. Specialist knowledge is required to install this type of towbar wiring, in some instances straight into the vehicle's lighting loom, although in most cases fitted in conjunction with a bypass relay (see more at bottom pf page).

Dedicated wiring is exactly as the name implies. Every kit is designed specifically for the vehicle that it is installed in, interfacing with vehicle systems as the manufacturer intended. The vehicle will know that a trailer is attached and will allow many features to adjust accordingly, in particular stability, suspension and road handling programmes.

Universal Wiring

Dedicated Wiring

Note: "Towbars Wales will not install wiring that may compromise either your safety or a vehicle's safety systems"

Bypass Relay

    Vehicle Re-Coder

              Combi Relay

A bypass, provides it's own power supply, thereby reducing the load and protecting your vehicle's lighting circuit.

In some instances after installation a vehicle will need to "learn" and adjust settings, this is the tool used.

A combi relay is used in conjunction with 12(S) wiring, it provides power to a caravan's fridge, lighting etc and will allow charging of leisure batteries whilst towing. Should your car battery need, it will automatically divert power to it.

audible warning for trailer indicators

universal installation

cheaper option

trailer stability control not activated

parking aids & fog lamps not disabled when towing

vehicle warranty may be at risk

trailer stability and other safety programmes activated

vehicle fog lights, parking aids disabled while driving

vehicle warranty protected

more expensive



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Towbars Wales
Orchard Lane



Towbars Wales are based in Crickhowell, Mid Wales.  A member of the National Trailer & Towing Association, we supply and fit equipment from EU approved manufacturers such as Tow-Trust, Witter, Westfalia and Brink.


Tel: 01874 437383
E-mail: info@towbarswales.co.uk
Web: www.towbarswales.co.uk

Opening Times:
Mon – Fri 9am to 5pm

Sat 9am to 1pm

Sun Closed