13 Pin Wiring Diagram Uk. 7 pin lighting connections (12n) trailer lights in the uk are normallly connected using a 7 pin plug and socket known as a 12n using a black cable. So brian you must be right about bailey wiring as this was one of the first with 13 pin.
The second diagram shows two brake lights, two indicators, two side lights and a fog light. In some cases and more often in europe the trailer light will be connected using a 13 pin plug and socket. Seems to operate as it should, but could it be part of the problem?
7 pin ‘s’ type plug and socket wiring diagram.
In addition, when installing a universal wiring kit, problems can arise that require additional expertise from the fitter. However i do think that the second page of the menber instructions you’ve posted above are somewhat misleading as the diagram of the pin numbering in the context of wiring a plug would make you think that you could use this as a visual guide while wiring the plug, i.e. The lower right hand terminal on the plug is pin 13. A universal wiring does not support or badly supports many (safety) functions of your vehicle.