ISO standards for trailer connectors

The 13-pin version being phased in is newer, provides more services than the 7-pin, a more positive locking and also better protection against moisture and contamination.

Heavy trucks that may have 12V systems are usually older (vintage vehicles) or on non-European markets.

Physical design of the standard ISO 11446[2][3] but also called Jaeger-connector from the company that developed it.

[11] Joining the pins for right and left tail lights (58R and 58L) can cause problems on German cars where it is possible to activate Standing Lamps on only one side of the vehicle.

[12] According to DIN 72552 pin 54G was initially intended for electrical control of brakes on trailers.

A few examples: This is why in regions using this connector, trailers on the road are occasionally seen with the rear fog lights on when they should be off.

[4][15] Signals in this connector (if following the standard) are not generally legally required (local regulations may still apply), which means that it is not mandatory to connect it if it is present.

The difference is that an additional connection for ground and that battery charging in the trailer is shared with other consumers.

This connector is sometimes present on vintage vehicles and the actual wiring may be completely different from what the standard states which means that measuring before connecting is a good idea.

The following supplementary information exists for the connector: The physical design is also used by SAE J560 with basically the same configuration.

The difference is that SAE J560 uses 12V (larger wire cross-section and higher amp rating on fuses).