Talking tyres - everything you need to know about trailer wheels to keep your business moving
Posted on 10-05-2023
The 12S wiring system is the supplementary wiring used largely on older style caravans built in the UK, and is used alongside the standard 12N wiring. The 12S system provides auxiliary power for other systems such as fridges. This system is now obsolete as far as new trailers go, having been replaced by the new European 13-pin system on all current caravans.
Below is the wiring diagram for the 12S system (click on the picture for an enlargeable image).