| Watling Tow Bar Fitting Service
Here at Watling Engineers we offer a comprehensive towbar fitting service for all makes and models of vehicle. Our specialist tow bar fitting workshops located near St. Albans in Hertfordshire are dedicated to all aspects of towing and we have the experience to take on jobs that often no one else will do. Please contact us for a quote.
Along with our own extensive range of towbars, we also supply towbars from other leading manufacturers including Witter, PCT, Brink, GDW and Bosal.
Towbar Fitting
| Our tow bar fitters are carefully trained and experienced at working on all types of vehicles from cherished classics to complex modern cars, vans, motorhomes and commercial vehicles. We fit towbars from our own extensive range of WATLING designs and also from the comprehensive lists from the WITTER, BRINK, PCT, BOSAL and GDW towbar ranges, giving you a wide selection of choice covering virtually every vehicle that is permitted to tow. Towbars are fitted to manufacturers nominated mounting points or, for the special designs, to carefully selected strong points on the chassis. All bolts used are high tensile grade 8.8 and torqued to the recommended tension. Please contact us for a quote |
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When choosing a tow bar, there are a number of considerations to take into account, and these include the type of towball attachment and whether or not you require it to be detachable.
There are 2 basic types of towball, which are the 2 bolt flange type and the swan neck. Both of these can be detachable but have different visual impacts and additional uses. For example, the 2 bolt flange type can be used for many more additional products such as cycle carriers, stabilisers and bumper protectors, but the swan neck offers cleaner lines and is more compatible with Al-Ko style caravan couplings. Be sure to specify your preferences before ordering and we will do what we can to find the right towbar for you.
Type Approval and European Law 94/20EC
Most passenger cars registered after 1st August 1998 (S registration) must be fitted with a Type Approved towbar. These cars have an “e” mark on the VIN plate together with the maximum car and trailer mass. If the trailer mass is not specified then the car is not permitted to tow a trailer, however it may still be fitted with a support bracket to fit a cycle or motorbike carrier.
European regulations were introduced on 1st August 1998 to harmonise the testing and approval of towbars throughout the EU. The regulations apply to all passenger vehicles registered from 1st August 1998 (S registration) which have to have an "e" mark and its maximum vehicle and trailer masses stamped on a plate. The vehicle manufacturer has to nominate the mounting points for the towbar and the towbar manufacturer has to design to fit to these only. The towbar (not the vehicle or the trailer attached to it) is then tested on a jig, to a formula to ensure it is strong enough to pass the test.
Here at Watling Engineers we fully comply with these regulations and where required we fit EU Type Approved towbars.
These regulations DO NOT APPLY to the following vehicles:
Commercial Vehicles (ie. pick-ups, chassis cabs, vans etc.), Motorhomes, Special Imports (ie. from Japan or America), Front towbars and other cars that are not “e” marked.
Towbar Wiring
An important but often overlooked aspect of towbar fitting is the wiring required to power trailer lights and caravan internal electrics.
The basic wiring to the plugs and sockets is fairly straightforward, however the fun starts when you are required to fit audible buzzers, relays and bypass units to cope with the increasingly complicated cars of today.
We are fully conversant with all aspects of towbar wiring and are stockists of Ryder electrical equipment who are market leaders in the field of towing and trailer electrics and have a reputation for quality and durability. |
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Towbar Wiring Guides
Listed below are some basic 12N and 12S type wiring diagrams that will help in vehicle wiring for both road lights and caravan internal electrics.
Alternatively, we are willing and able to look at any wiring problem here at our workshops.
WIRING DIAGRAM FOR 12N TYPE 7-PIN Black socket or plug
for vehicle road lights
| Colour |
Terminal |
Purpose |
Looking at the Socket towards the plug.
Looking at the Plug towards the socket. |
| Yellow |
1 (L) |
LH Indicator |
 |
| Blue |
2 (54G) |
Rear Fog Light (or Aux.) |
| White |
3 (31) |
Earth |
| Green |
4 (R) |
RH Indicator |
| Brown |
5 (58R) |
RH side Light Stop |
| Red |
6 (54) |
Lights |
| Black |
7 (58L) |
LH Side Light |
WIRING DIAGRAM FOR 12S TYPE 7-PIN Grey socket & plug
for caravan & trailer interior power.
| Colour |
Terminal |
Purpose |
Looking at the Socket towards the plug.
Looking at the Plug towards the socket |
| Yellow |
1
|
Reverse Light |
 |
| Blue |
2 Pre 1/97
2 Post 1/97 |
Battery Charging or Power |
| White |
3 |
Earth |
| Green |
4 |
Power or Battery Charging |
| Brown |
5 |
Warning Light for pin 1 |
| Red |
6 |
12V Refrigerator |
| Black |
7 |
Spare |
WIRING DIAGRAM FOR 12N TYPE 7-PIN INCLUDING REAR MOUNTED AUDIBLE BUZZER for most cars that do not require bulb failure bypass relays
WIRING DIAGRAM FOR SELF SWITCHING RELAY ON 12S SOCKET
WIRING DIAGRAM FOR DOUBLE RELAY ON 12S SOCKET
TROUBLE SHOOTING
FIRST: Check and test the fuses on all circuits
SECOND: Ensure that there is a good clean EARTH connection to the vehicle body, the 7-pin socket, the trailer 7-pin plug and the trailer lamp units.
If one circuit does not function check and test the fuses, check and test the bulbs.
If fuses continue to blow, calculate that the fuse is the correct size for the load on the circuit (Watts/Volts = Amps eg 4x21w / 12v = 7A). The fuse rating should be approximately twice the load to allow for surges.
Look for a “short circuit” – bare wires or contacts touching Earth along the loom, the socket, the plug or in the lamp units.
If any bulbs flash or dim out of sequence, check ALL the earth connections.
Other checks you can do include:
- Clean off all paint, dirt or rust from around the earth point, fix a ring tag to the white wire from the 7-core and fix securely to the earth point, smear with petroleum jelly.
- Clean the bulb contacts and holder.
- Test the other six wires for continuity across the connectors and to the lights.
- Test the screw connections in the socket, if there is any sign of corrosion replace the socket. Discard any socket covers or rear seals as these only promote corrosion through condensation, ensure drainage from the socket. Ensure that the 7-core is lead through grommets in metal surfaces and prevent chaffing at any point. Clip the 7-core back to one of the socket screws with a P-clip.
- Check and clean the individual pins in the socket, spreading the male pins slightly.
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