ISO 11446:2004 specifies a 13-pole electrical connector between towing and towed vehicles with 12 volt electrical system. It was developed in 1987 by Erich Jaeger[1] to replace older 7-pin plugs.

ISO 11446
Type Trailer Connector
Superseded ISO 1724 (12N)
ISO 3732 (12S)
General specifications
Pins 13
Pinout
Pin 1 Left indicator
Pin 2 Rear fog lamp
Pin 3 Ground [a]
Pin 4 Right indicator
Pin 5 Right tail lamp [b]
Pin 6 Brake lamp
Pin 7 Left tail lamp[b]
Pin 8 Reverse lamp
Pin 9 Permanent power
Pin 10 Switched supply (for fridge)
Pin 11 Ground for pin 10 [a]
Pin 12 Trailer Presence Detection[c]
Pin 13 Ground for pin 9 [a]

13-pin female socket (ISO 11446)

Notes

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  1. ^ a b c Pins 3, 11 & 13 must not be joined in the trailer to prevent ground loops
  2. ^ a b Pins 5 & 7 must not be joined in the trailer without a pair of diodes
  3. ^ Pin 12 was assigned prior to 2012; older vehicles could be using this for a different function

References

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  1. ^ "ISO 11446 - the JAEGER system for trailer connectors".

Sources

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