The 13-pin wiring system has historically been the standard European wiring for all trailers and caravans. More recently it has replaced the old style 12N/12S wiring system usually found on caravans built in the UK.
Since the introduction of European Whole Vehicle Type Approval legislation in 2014, it became necessary for trailer manufacturers to fit a reverse light to all new build trailers. This means that the old style 7-pin wiring system is no longer viable, and had to be replaced by a new 8-pin system. These systems are derived from the European 13-pin plugs and sockets, with 5 of the pins removed to provide an 8-pin system.
Below is the wiring diagram for the 13-pin system. For an 8-pin wiring system you just need to connect up the first 8 pins in the table below (click on the picture for an enlargeable image).
