Written by If you are looking trailer/caravan or towbar wiring it is important not to get the two following connector types mixed up. Hopefully this will clarify:
Type 12N Plug
Trailers must be equipped with sidelights, brake lights and indicators. This is done via a type 12N plug which is the most common connection found fitted to the rear of vehicles.
See trailer plug wiring for more details
Type 12S Plug
The type 12S connector on a towing vehicle is for supplying the supplementary power required by the caravan/trailer reversing lights. On a caravan it is also used for interior lights, battery charger and fridge.