The electrical sockets supplied with towbars in the UK fall into the following 3 types. Your decision will likely be based on which type of plug your equipment has, but please take time to read this information about what happens behind the socket:
12N is the designation for the 7-pin lighting socket, used when towing just a trailer or caravan (without the need for charge of auxiliary battery). In the UK it has all the functions for the rear lights on a vehicle except for reverse.
12S is an additional 7-pin socket mainly used when towing caravans. It consists of a permanent 12v power supply, and a switched 12v power supply for the fridge and auxiliary battery (UK). It also contains a feed for the reverse lights on the caravan.
The modern 13 Pin Euro Plug & Socket Wiring combines the features of both conventional 12N and 12S sockets to power both trailer/caravan lighting and auxiliary equipment such as battery charging, refrigerator etc. 13 pin sockets are being fitted to all caravans and trailers sold from 2009. It can be wired with the same functions as both the 12N and 12S sockets, or with just the lighting functions including reverse (required on all trailers and caravans from 2010).
Once upon a time, the towing electrics served purely to provide lighting to a trailer / caravan, and to charge batteries and run fridges in a caravan. All we had to do was choose between a Single or Double socket system.
TIMES HAVE CHANGED!
The rapid development of vehicle electronics and use of CANbus systems (basically an onboard computer network), have enabled vehicles to make changes to their settings depending on what it will be doing. You may have seen cars with ‘eco mode’, ‘sports mode’ or ‘city mode’ options, and although you may not be aware of it, most cars effectively now have a ‘towing mode’. This is not a button you press, but something that automatically makes changes when you put a plug into your towing socket, and turns off when you remove it afterwards.
What kind of changes?
Well, each manufacturer and model will have different combinations, but some of the more common include changes to, or activation of :
Trailer Stability Programmes (TSP)
Brake electronics Suspension systems
Engine electronics Engine cooling system
Cruise control including ACC
Bulb failure systems
Lane changing assistants
... and yes, many of these feature on vans and commercial vehicles too!
WHAT ABOUT A UNIVERSAL BYPASS SYSTEM?
It is true that the majority of vehicles in the UK are still being fitted with what is referred to as a Universal or 7way bypass relay, and in the event that Yorkshire Towbars are unable to source an appropriate dedicated electric system, we too are forced to fit these systems.
It is however our Policy to ONLY fit Vehicle Specific Wiring Kits if they are available to us. In our opinion, Bypass relays are a Make-do, not a proper solution.
To illustrate this may we use the analogy of the wheels on a car:
The manufacturer specifies the size and rating of the wheels and tyres (but not the brand), in order for the owner to be as safe as possible. If these wheels were to be replaced by ‘space saving’ temporary wheels and tyres, the car would still drive. There even a strong likelihood that they could exceed the recommended safe tyre speed limit (usually around 50kph), and still not fail.
However, logic tells us that this is not a clever thing to do, even if we only ever potter around town, and spending a little more for the correct wheels is the course of action most would take. Similarly, whilst bypass relays might ‘do the job’, logic tells most of us that it is worth spending a little more for the correct system.
Consider the following statements:
Bypass relays will void any manufacturer warranty that your vehicle has remaining
For those who may have been referred to the EU Block Exemption rule as an argument to this, it is worth noting that this European directive allows the use of non manufacturer parts BUT ONLY IF THEY ARE OF EQUAL QUALITY AND FUNCTION! The bypass relay is not!
Bypass relays protect your vehicle’s electronics
Maybe it would be better to say that they are less likely to cause a problem with your vehicle’s electronics, than would be the case if one is not used. The bypass relay HIDES from the car the fact that you are tapping into its system. On the, admittedly rare, occasions that they go wrong, customers are reporting bills regularly in excess of £3000 to make good the damage caused, and of course, this is not done under warranty!! Do you fancy the odds of it not being you?
Bypass relays don’t affect your vehicles performance
You could argue that this is TRUE!
But remember that they do not allow any safety changes to take effect by informing your vehicle that it should activate ‘Towing mode’ either.
Bypass relays don’t invalidate your Insurance
Again, this is for the most part TRUE. However, there are now some Insurers who may not pay out fully on a claim if safety features present on a vehicle have not been activated and may have prevented an accident. Bypass relays do not activate them.
Dedicated kit installed – Can you spot it?
It can be a very involved job on modern vehicles!
But considering the alternative, we think it’s worth it!