Tow Bar Wiring
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 draw the power from) that vehicles light circuits.
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 –:
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They are specially designed to work with your vehicle’s electrical system
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Some will communicate with other vehicle control units to alter vehicle settings accordingly
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They can usually activate, if fitted, a dash trailer indicator warning light
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Automatic deactivation of factory-fitted parking aids
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They automatically disable a vehicle’s rear fog lamps when towing to reduce reflective glare
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They automatically activate the TSP (Trailer Stability Program), if installed
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The automatic lockout of speed-dependant adjustable suspension, if installed. This can be a critcal safety issue when towing.
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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.
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They provide the safest, most reliable and long-lasting type of towing connection.
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They meet or exceed your vehicle’s warranty requirements.
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They allow the full function of the vehicle’s towing safety features to be used
NB. Aftermarket 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 coming down in price as availability increases.