A Guide To Tow Bar Wiring

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To find the right tow bar electrics for your vehicle click on the find by vehicle tab and then select your vehicle manufacturers name or email info@budettowbars.co.uk with your vehicle details

Tow bar wiring electrics enable the towed trailer or caravan to be electrically connected to the towing vehicle to power the legally required road lights amongst other things. Basically, there are two types of towing electrical kits Universal Fitting and Dedicated Tow Bar Wiring kits

Universal Fitting Tow Bar Electrical Kits

Universal fitting electrics are the traditional way of adding towing electrics to a vehicle. They are offered in 7 pin and 13 pin format  to run lights only (formerly referred to as single or 12N) or to run caravan electrics (formerly known as double or 12N & 12S electrics) with or without a 7 way Bypass relay. The Bypass relay is used when the vehicle to be fitted has CANbus or multiplexed rear lighting circuits (E.G. bulb failure dashboard indication) which are extremely sensitive to any changes in power draw. The bypass connects to the vehicles lighting circuits but only to take a signal from the circuit to operate the towing electrics, the power for that respective light circuit comes from the relay and therefore ” bypasses” (does not change the power draw on) the vehicles light circuits.

Are you only going to tow a trailer?

If so, a 7 Pin 12N Electrical Kit is needed. This will operate the trailer or caravan indicators, brake lights, fog lights and side lights. This kit has one connector on the towing vehicle.

Are you only going to tow a caravan manufactured before 2009?

If so, a 7 Pin 12N/12S “Double” Towbar wiring kit is needed. This will operate the caravan or trailer indicators, side lights, brake lights, fog lights and reversing lights and also provide supplementary power to the caravan for a fridge and other electrical equipment. This kit has twin 7 pin sockets (black and grey) to match the connectors on the caravan.

Are you going to tow a caravan manufactured after 2009?

The 13 Pin “double” universal kit provides the same functions as the 7 Pin Universal Twin Electrics Kit but has a single 13 Pin Euro socket. This type of connection is becoming more popular because it operates all the necessary lights on the caravan or trailer and also allows you to have the supplementary power for a fridge etc from a single socket connector on the vehicle. These pin connections lock the plug to the socket to give a more reliable connection when underway and are less likely to burn out.

N.B. All towing electric installations are required to have an audible or visual alert to tell the driver when the towed vehicle indicators are not working. If you are not using a 7 way bypass (which has a built in audible tell-tale) then another tell-tale should be installed. The most popular solution is a rear audio warning device which comes as standard in kits without a bypass relay.

Dedicated Tow Bar Wiring Kits

Whilst the Universal fitting electrical kits detailed above are perfectly adequate in many cases, vehicles of today can have extremely sophisticated computer-controlled electrical systems that monitor engine, lighting, braking and other mechanical performance. Some can automatically enable towing-related safety functions (such as Trailer Stability Program – TSP – which helps to prevent snaking)  to operate when you electrically connect a caravan or trailer to the vehicle. For this reason and particularly for vehicles with built in towing-related safety functions, a dedicated towing electrics kit may be obligatory to avoid any insurance issues in the event of an accident whilst towing.

The advantages of Dedicated electrical kits are –:

  • They are specially designed to work with your vehicle’s electrical system
  • Some will communicate with other vehicle control units to alter vehicle settings accordingly
  • They can usually activate, if fitted, a dash trailer indicator warning light
  • Automatic deactivation of factory-fitted parking aids
  • They automatically disable a vehicle’s rear fog lamps when towing to reduce reflective glare
  • They automatically activate the TSP (Trailer Stability Program), if installed
  • The automatic lockout of speed-dependant adjustable suspension, if installed. This can be a critical safety issue when towing.
  • Provision of a pre-allocated fuse position on the main fuse board, (often listed in the owner’s handbook) allows safe/stable power draw from your vehicle which is critical when your vehicle has state-of-the-art engine monitoring.
  • They provide the safest, most reliable and long-lasting type of towing connection.
  • They meet or exceed your vehicle’s warranty requirements.
  • They allow the full function of the vehicle’s towing safety features to be used

NB. Dedicated kits are not available for all vehicles and Universal fitting kits may be your only option. Some vehicles may need coding which may have to be done at the vehicle main dealer’s workshop and can incur a modest additional cost. Dedicated kits may cost significantly more than universal fitting electric kits but are increasingly coming down in price as availability increases.

Which Dedicated Electrical Kit do you need?

Towing a pre- 2009 caravan or trailer without reverse lights or supplementary power?

The 7 Pin Dedicated Single Electrics Kit operates the caravan or trailer lights, indicators, brake lights and fog lights but DOES NOT supply reversing lights or supplementary power for the caravan equipment. It is a single socket connection.

Towing a pre- 2009 caravan or trailer with reverse lights and supplementary power?

The 7 Pin Dedicated Twin Electrics Kit is not normally available in a dedicated towing electrics format. This may change over time but a low cost converter cable can be purchased to convert a 13 pin full function dedicated kit to be able to connect to a caravan with two 7 pin (12N & !2S) plugs

Towing a caravan manufactured after 2009?

The 13 Pin Dedicated Kit offers everything that the 7 Pin Dedicated Twin Electrics kit does but through a single socket ISO 13 pin connection which is far superior to the push fit 7 pin type socket

NB. Increasingly, tow bar/ball mounted cycle-carriers and European-manufactured trailers are using the 13 pin system as this offers a more secure locked-in-position connection.

FAQs

What is coding and does my vehicle need to be coded?
Coding is the process of pluging a scanner into the vehicles OBDII port and sending instructions to the vehicles ECU(s). It is increasingly common when servicing or installing replacement parts. If coding is required to enable the towbar wiring kit to operate, it will be listed in the product description.  Some times coding is required just to activate the vehicles built in towing related safety features such as auto fog-light cut off.  Some times nothing will work until coding is completed. See the fitting instructions for the towbar wiring kit being considered for more information about what if any coding is required. Be aware not all coding devices are capable of coding towbar wiring installations, please confer with your coding device manufacturer or use the coding device suggested in the fitting instructions.
What is trailer prep?
Trailer prep is found on many modern vehicles. If it is not known if the vehicle to be installed may have trailer prep or not look at the product listings to see if their are kits listed with "+ Prep" or not. If so, it is an important factor when deciding which towbar wiring to install. If  "+ Prep" options exist a physical inspection of the vehicle to locate the trailer prep plug(s) will be required or a call to the main dealer to ask if trailer prep was installed during the vehicle build? Use the installation instructions for the "+ Prep" wiring kits if opting for the physical inspection to locate the plug(s) if present. If your vehicle has trailer prep order towbar wiring kits with "+ Prep" in the product title and description. If no trailer prep plugs are located or if the installer is not bothered about connecting to the trailer prep plugs, select kits for vehicles with and without trailer prep or those with no mention of trailer prep in the product description. It's often worth the effort to find out if the Vehicle has trailer prep because they are quicker and easier to install towbar wiring on to and cost less than the same wiring kit for the vehicle without trailer prep.
Will this item fit my vehicle?
When ordering a towbar or towbar wiring for your vehicle, you will need to know the make, model and build year of your vehicle. If these match the details shown in the product headline and description then the item will fit your vehicle subject to whether the kit fits vehicles with trailer prep. See What Is Trailer Prep if uncertain or email info@budettowbars.co.uk for further help.
Can I return my order for a refund?
In most circumstances, yes. Please Note however, that the accessories we supply are specialist parts and are often MADE To or SPECIAL Order items. Returns are not offered on made to or items that have been fitted. Special order items incur a minimum restocking charge of 25% of their value plus return carriage fees. Please check the individual full product description to find if it is a made to or special order item prior to ordering. To help our customers to avoid the costs and inconvenience of returns we will contact you to confirm the item purchased is correct for your specific vehicle and needs prior to dispatch. If your order is urgent please contact us prior to ordering For more information about refunds and returns please click here
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