Main menu:
Tow Bars
Towing Electrics
What type of electrics do I need?
This is a matter of personal choice and circumstance, with three types of electrical kits and four types of connectors commonly available in the UK.
You would usually have the connector fitted that matches that of the connector on the caravan, trailer or light board. The type of electric kit will depend on your budget, which company is fitting it and availability. Not every kit is available with each connector, some may be available from one supplier but not the other, and you may have to shop around for different specifications.
Which kit will fit to my car?
It is possible that there will be a universal or original equipment dedicated unit that will be available to fit to your vehicle. Which kit you decide to have fitted will depend on several circumstances.
Should I have a ‘Universal’ electric kit?
As the title suggests, these kits will be suitable for most vehicle types, but are non-specific and require prior vehicle knowledge or research to fit them. There are two types: a basic kit, that draws power from the vehicle’s own lighting circuit and a bypass kit, which utilises a dedicated power supply and uses the vehicle’s lighting circuits as signals to switch relays.
Fitting a universal type of kit is the cheapest and can sometimes be the quickest method but has limited functionality and user benefits. However, this type may not be suitable for certain vehicles, especially those with sophisticated electrical systems; professional advice prior to installation is recommended.
Which type of connector should I have fitted?
You can have either single, double, 13 pin electrics fitted to your vehicle, which type will depend on several circumstances.
Single |
Twin |
13 pin |
Dedicated kit |
|
Trailer |
Yes |
Some |
Some |
Yes |
Trailer Tent |
Yes |
Some |
No |
Yes |
Bike Carrier |
Yes |
No |
Some |
Yes |
Jet ski |
Yes |
No |
No |
Yes |
Horse Box |
Yes |
No |
No |
Yes |
Caravan |
Yes |
Yes |
Yes |
Yes |
Boat Trailer |
Yes |
No |
No |
Yes |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Should I have a 12N 7 pin single electric connector?
This is the most common and cost effective type of connector currently used in the UK. It will fulfil all Normal towing requirements under UK law and can be used with lighting boards, cycle carriers, caravans, garden trailers, plant trailers and horseboxes. In fact, almost anything you can connect to a towbar.
Pin Number |
Colour |
Function |
1 |
Yellow |
LH Indicator |
2 |
Blue |
Rear Fog Light |
3 |
White |
Earth |
4 |
Green |
RH Indicator |
5 |
Brown |
RH Tail Light |
6 |
Red |
Stop Light |
7 |
Black |
LH Tail Light |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Should I have a 12N 12S, 7 pin double electric connector?
This consists of a Normal connector as above and a similar extra Supplementary connector that can supply a caravan, horse box or tipper trailer with a switched and permanent twelve volt power supply, extra earth connections and a reverse light facility. A 12S socket is only required if you wish to charge the battery and power the fridge when travelling. Having both connectors on the towbar can be bulky and unsightly especially when fitted to a detachable towbar.
Pin Number |
Colour |
Function |
1 |
Yellow |
Reverse Light |
2 |
Blue |
Aux Battery |
3 |
White |
Earth |
4 |
Green |
Permanent Live |
5 |
Brown |
Spare |
6 |
Red |
Fridge |
7 |
Black |
2ND Earth |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Should I have an ISO 13-pin connector?
This is a single connector of similar size to that of a 12N connector but it contains both 12N and 12S functions in one. It is a waterproof connection with a unique twist lock system for safe and reliable contact.
The socket is smart and discreet, ideal for towbars with a swing away socket plate. The cost is higher than having separate 12N/12S connectors. However, as all UK caravans manufactured after 2008 will have a 13-pin connector as standard this will soon become a popular choice.
Pin Number |
Colour |
Function |
1 |
Yellow |
LH Indicator |
2 |
Blue |
Fog Light |
3 |
White |
Earth |
4 |
Green |
RH Indicator |
5 |
Brown |
RH Tail Light |
6 |
Red |
Stop Light |
7 |
Black |
2ND Earth |
8 |
Yellow |
Reverse Light |
9 |
Green |
Perm Live |
10 |
Red |
Switched Power |
11 |
Black |
Earth for pin 10 |
12 |
NA |
Spare |
13 |
White |
Earth for pin 10 |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Should I have a bypass relay fitted?
Many modern vehicles have computerised vehicle electrical systems often known as CANbus systems. Vehicles using CANbus wiring may require fitment of a bypass relay or even vehicle specific wiring kit when fitting towing electrics. Some vehicles may also require a computer software update to modify suspension settings whilst towing.
Pin Number |
Colour |
Function |
1 |
Yellow |
LH Indicator |
2 |
Blue |
Rear Fog Light |
3 |
White |
Earth |
4 |
Green |
RH Indicator |
5 |
Brown |
RH Tail Light |
6 |
Red |
Stop Light |
7 |
Black |
LH Tail Light |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Charging relays
Auxilliary Power supply and refridgerator wiring from the vehicle should be supplied via a relay wired to activate only when the vehicle engine is running, to prevent high current draw from the auxilliary battery as the vehicle starter motor operates. This power circuit should also be fitted with a fuse close to the vehicle main battery.
Pin Number |
Colour |
Function |
1 |
Yellow |
Reverse Light |
2 |
Blue |
Aux Battery |
3 |
White |
Earth |
4 |
Green |
Permanent Live |
5 |
Brown |
Spare |
6 |
Red |
Fridge |
7 |
Black |
2ND Earth |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Should I have a dedicated electric kit fitted?
These kits are vehicle specific, and have all the user benefits of the original equipment kit, but without the cost premium. However, availability can sometimes be an issue especially with new vehicle models. They are usually 30-50% cheaper than original equipment kits, but can take longer to fit than the cheaper universal kit. A dedicated kit is designed to be fitted to a specific vehicle.
Modern vehicles are packed with inteligent safety features. Vehicle systems may include features for towcars to increase stability and safety whilst towing or to adapt safety systems to account for added load and different handling whilst towing such as:
- Interactive/self leveling suspension
- Crash anticipation
- Hill start assist
- Intelligent braking
- Electronic stabilisation program (esp)
- Fog lamp cut off
- parking sensor cut off
Here at Advanced towing UK have the facilities to install these kits to most vehicles. Please be aware If you are fitting your own towbar or are having one installed elsewhere and you use a bypass relay none of the above functions will work as the vehicle does not know that it is actually
towing a trailer or caravan.
* A software download may be required to activate certain features. (may incur a charge).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Top tip
A common fault with trailer electrics results in all lights dimming and flashing when brake or indicators are switched on can be caused by a bad earth return connection on vehicle or trailer wiring, possibly due to corrosion at a wiring plug.
Sub-Menu: