A 13-pin trailer socket follows the ISO 11446 standard and is commonly used in Europe for caravans, trailers, and bike carriers. It provides both road lighting functions and supplementary power for things like reversing lights and caravan charging.
13-Pin Trailer Socket Wiring Colours and Functions
Pin No. | Wire Colour | Function | Notes |
1 | Yellow | Left Indicator (L) | Flashes when indicating left |
2 | Blue | Rear Fog Light (54g) | Turns on with vehicle fog lights |
3 | White | Earth (Return for Pins 1–8) | Main ground connection |
4 | Green | Right Indicator (R) | Flashes when indicating right |
5 | Brown | Right Tail Light / Number Plate Light (58R) | Permanent tail light on right |
6 | Red | Brake Lights (54) | Activates with brake pedal |
7 | Black | Left Tail Light / Number Plate Light (58L) | Permanent tail light on left |
8 | Pink | Reverse Light (R) | Activates when reversing |
9 | Orange | 12V Permanent Power (30) | Live feed from battery (fused) |
10 | Grey | 12V Ignition-Switched Power (15) | Powers appliances when ignition is on |
11 | White/Black | Earth (Return for Pin 10) | Separate ground for switched power |
12 | White/Blue | Not Always Used (e.g., Trailer Detection) | Can be for special functions |
13 | White/Red | Earth (Return for Pin 9) | Separate ground for permanent power |
Important Notes
Pins 1–8 handle the standard road lighting functions.
Pins 9–13 handle power supply functions, used mainly in caravans.
A split-charge relay is often used to prevent draining the towing vehicle's battery.
Always use correct fuses and check for secure connections to avoid faults.
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