Fitting Instructions for all 12S Kits and Relays General Instructions for Wiring 12S Socket to a Vehicle (12 Volt Negative Earth) Wire the socket as shown in Chart 'B' Take the Grey 7-core (or 13-core) cable into the boot through a suitable entry point.. Trailer Electrics Trailer Electrics for sale - The Towing Warehouse stocks a wide range of trailer electrics including 12N 12S & 13 pin euro plugs / sockets, tow bar wiring relays, junction boxes & various cabling, we also stock plug converters and extensions etc. Trailer Electrics & Accessories for sale here TEB7AS Fitting Instructions.
In order to avoid mal-functions and damage to the vehicle's electrical system the earth terminal must be disconnected from the vehicle's battery before starting work!. 12N (Normal) Socket & Plug Wiring. 12S (Supplementary) Socket & Plug Wiring. About the Author: Chris Hood Chris Hood is a Director of Western Towing, bringing over 23 years of hands-on experience in towbars, trailers, and towing solutions.