Below is a diagram for the original plug and socket showing the functions of each pin. If your truck has a built in 7 pin socket but you only need 5 of the pins.

Wiring Diagrams For 7 Pin 12n N Type Trailer Lights Caravan
Uk 7 pin trailer socket wiring diagram. If you have a 13 pin socket fitted to your vehicle adaptors to plug in so you can use a normal 7 pin plug are available. The 7 pin n type plug and socket is still the most common connector for towing. You will need twin electrics if you require more power than what a single 7 pin socket can provide on a pre 2008 manufactured uk caravan post 2008 uk caravans are fitted with 13 pin connectors. Wiring diagram for double relay on 12s socket. In some cases and more often in europe the trailer light will be connected using a 13 pin plug and socket. Part 1 of 2 how to properly wire a trailer in the uk using a 7 pin plug.
In the trailer wiring diagram and connector application chart below use the first 5 pins and ignore the rest. 7 pin trailer wiring diagram with brakes 7 pin flat trailer wiring diagram with brakes 7 pin rv trailer wiring diagram with brakes 7 pin trailer wiring diagram with brakes every electrical arrangement is made up of various different parts. All diagrams are as viewed from the cable side see example above. Wiring diagram for self switching relay on 12s socket. This supplies power to the road lighting of your trailer or caravan. The 7 pin flat plug will fit into a 12 pin flat socket and work perfectly.
Each component ought to be set and connected with different parts in particular manner. 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. The diagram below shows the view from outside the vehicle socket under the flap and from inside the trailer or caravan plug. Plug size is similar to an australian 10c coin. Trailer wiring electric brakes tip by. The table and diagram below explains the connections used on a 7 pin setup.
Small 7 pin round qld identifying. How to wire a 7 pin trailer plug diagram shown skip navigation. Please like and subscribe. This is the standard uk wiring of a the normal socket and plug otherwise known as 12n. How to wire up a uk trailer lighting plug. Use the 7 pin connector anyway see below and just leave out the last 2 wires.
This has now been replaced by 13 pin euro plugs on all new caravans. This is an extension of the 7 pin flat. If not the arrangement will not function as it ought to be. Twin electrics is a 2 plug system which combines the single 7 pin 12n electrics socket with a 12s electrics socket. Check and test the fuses on all circuits.