10/01/2017
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Towbar Advice: Ready to Tow

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Fixed or detachable, electric kits, LED rear lights, car electronic control computers… All you need to know about towbars, towballs and electrical connections is here.

Our technical writer, Terry Owen, guides you on how to choose the right towbar for your needs and what’s involved in electrical connections.

Fixed towball vs. detachable vs. retractable

Westfalia detachable towball

Towbars with fixed towballs are often cheapest and are easy to use as there is nothing to deploy. Detachable types look neater if you can be bothered to remove the towball when not in use. Beware that, if you don't remove it, thieves might. Thefts of detachable towballs are becoming a problem in some areas.

 

 

 

 

 

 

For the ultimate in neatness and convenience, you may wish to consider a towbar with a retractable towball. These swivel out of the way when not in use leaving little or nothing to be seen. The swivel action may be manual or electrically driven. Some of the latter have proved unreliable.

Westfalia retractable towball

 

 

 

Towing with an AL-KO hitch head stabiliser (AKS)

AL-KO's AKS stabilisers are quite bulky requiring flange mounted towballs to have an extended neck to provide the clearance for the stabiliser head to rotate. This is not normally a problem with swan neck type towballs.

L-KO's AKS stabiliser hitch

Above: AL-KO's AKS stabiliser hitch takes up more room than a standard hitch

AL-KO's extended neck towball

Above:  AL-KO's extended neck towball (left) alongside a normal one

Finding the right towbar

With so many towbars on the market, it can be difficult to know where to start. Witter's website is as good a place as anywhere. You can just enter your car registration number and see what Witter has to offer.

detachable flange towbar assembly from Witter

A detachable flange towbar assembly from Witter

If you don't know what you want, there are several other manufacturers to check out (see below), or you could go to an independent specialist such as PF Jones. They stock some 10,000 towbars of different makes and have vast experience in the field. In common with many other suppliers, they will arrange for a towbar to be fitted at your home or place of work.

Towbar manufacturers

  • Bosal Group
  • Brink Group
  • PCT Automotive
  • Tow-Trust
  • Watling Engineers
  • Westfalia Automotive
  • Witter Towbar

Electric kits

Two types of electric kit are available - vehicle specific and bypass. As the name implies the former are made to suit specific vehicles and, in conjunction with the coding of the car's ECU (see below), enable the vehicle to know when a caravan or trailer is attached and to modify its behaviour accordingly.

A vehicle specific wiring kit

A vehicle specific wiring kit

Bypass kits simply take signals from the car's rear lights and use them to switch relays which then power the lights on the caravan or trailer. The current drawn from the car's rear light circuits is tiny, and the car has no means of detecting that it is a tow vehicle.

Twin electrics vs. 13 pin

From September 2008 all UK built caravans adopted the single 13 pin plug that had been standard on the Continent for some years. The 13 pin 'plug-and-socket' is engineered to a higher standard than the old twin plug system and is less likely to be affected by pin burn or water ingress.

Twin electrics

Twin electrics

13 pin electrics

13 pin electrics

For these reasons is makes sense to go for a 13 pin set up. If you need to tow a caravan with twin electrics, adapters are readily available.

Vehicle coding

When a vehicle specific kit is fitted it is normal for the car's ECU (electronic control computer) to be reprogrammed accordingly. In this way, the car knows when it is being required to tow and can modify the responses of items such as the ABS, vehicle and trailer stability programs, ride height and transmission.

The operation is performed by the towbar fitter using a particular device plugged into the vehicle's OBD (on-board diagnostic) port.

 A car's ECU is updated using this device from Westfalia

A car's ECU is updated using this device from Westfalia

A small number of vehicles do not require this reprogramming. The latest Range Rover is one.

LED rear lights

LED lights

LED lights look the part but can cause compatibility problems

Caravans with LED rear lights may give unpredictable results when used with tow vehicles fitted with vehicle-specific wiring kits. This is because the current taken by the LED lights is so small the vehicle may not be able to detect them.

Until you plug the caravan into the car, you've no way of knowing what will happen. Generally speaking, cars which themselves have LED rear lights don't have a problem, but there's no guarantee.

If problems do arise, the first port of call should be the caravan dealer. There may be a modification that can be fitted to cure the problem.

DIY

While it's possible for a competent DIY person to fit a towbar it's not recommended. Apart from the issues with electrics mentioned above, the tow vehicle may require a significant dismantling of the rear bumper and crash beam, not to mention other items.

Top tip

Modern tow bars take the place of and perform the same function as the car's rear crash beam. When you have a towbar fitted you might wish to ask for the crash beam to be returned to you. This will then allow the car to be returned to its original condition, for example by a new owner.

rear crash beam

A rear crash beam being readied for removal

Further information

Further information on equipping your new towcar with a towbar click here.

 

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