Trailer Wiring Diagrams

This article will provide some tips for trailer wiring, showing you the various plugs and sockets used in Australia. There quite a few types out there, and some types are more predominantly used depending on the state you live in. Although there are some people who have the aptitude to test trailer, camper and caravan lights, diagnose faults, and even fix them - this article does not intend to be a replacement for an auto electrician (which is a trade), and instead should only be used as a guide.

Trailer wiring can be difficult to get your head around. As mentioned above, there are a number of connectors; from 5 pin round, 6 pin round, 7 pin round small, 7 pin round large, 7 pin heavy duty, 7 pin flat, and even a 12 pin flat - phew!! and not to mention all the adapters available, it can all be quite confusing. Well, we are not going to go too in depth with all these types - only the more commonly used ones.

The following diagrams and bullet points provide the Australian Standard for 5 and 7 pin plugs and sockets for trailers and caravans. Knowing these colour codes can save you the time consuming exercise of testing lights by means of trial and error. Also, an important thing to remember - it is the WHITE wire that is the earth in trailer wiring not the green or black wires. This applies to all types of trailer plugs used in Australia.

More information can be found on the Australian Government's - Department of Infrastructure, Transport, Regional Development and Local Government website.

This type of plug and socket is an older type of connector. A minimum 7 pin connector (that comply with Australian Standard 2513-1982) has been mandatory on all new trailer units registered after January 1, 1988, thus allowing sufficient connections to cope with all lighting requirements and electric brake controls. These trailer plugs and sockets may be found in Victoria, Tasmania, South Australia, and the Northern Territory.

• Pin 2 - Yellow - Left-hand turn indicator


• Pin 3 - White - Earth return


• Pin 5 - Green - Right-hand turn indicator


• Pin 6 - Red - Stop lamps


• Pin 7 - Brown - Rear lamps, clearance & side marker lamps

This type of plug and socket is also an older type and vehicles that were first registered before January 1988 commonly used a 6 pin type. A minimum 7 pin connector (that comply with Australian Standard 2513-1982) has been mandatory on all new trailer units first registered after January 1, 1988 - thus allowing sufficient connections to cope with all lighting requirements and electric brake controls. This type of connector may be found in the states of Western Australia, Queensland, and New South Wales.

• Pin 1 - Brown - Rear lamps, licence & clearance lamps


• Pin 2 - Yellow - Left-hand turn indicator


• Pin 3 - Green - Right-hand turn indicator


• Pin 4 - Red - Stop lamps


• Pin 5 - Blue - Auxiliary circuit/service brakes


• Pin 6 - White - Earth return

There is a large and small variety of this plug and socket type. Type 1 is the large 7 pin connector type with a PCD (Pitch Centre Diameter) of 20mm, whilst Type 2 is the small 7 pin connector type with a PCD of 13mm. The larger round Type 1, 7 pin plug seems to be quite popular in Victoria. Both Type 1 and 2 plugs have a locating notch at the bottom. For reference - a Type 3 connector is the flat variety and this comes in 7 pin and 12 pin.

Please note that because of interchangeability problems that may arise, it is recommended that pin number 5 in the 7 pin connectors be used only for service brakes. If auxiliary circuits are required, then the 12 pin Type 3 connector would be preferable.

7 pin connectors are mandatory on all new trailer units first registered after January 1, 1988, allowing sufficient connections to cope with all lighting requirements and electric brake controls. Since the introduction of the mandatory 7 pin connector, all wiring connections have been standardised and the use of a specific trailer cabling involving seven wires and standardised colouring has also been adopted. The 7 pin round Type 1 and Type 2 connectors are found in all states and territories throughout Australia.

• Pin 1 - Yellow - Left-hand turn indicator


• Pin 2 - Black - Reversing signal


• Pin 3 - White - Earth return


• Pin 4 - Green - Right-hand turn indicator


• Pin 5 - Blue - Service brakes


• Pin 6 - Red - Stop lamps


• Pin 7 - Brown - Rear lamps, clearance and side marker lamps

This connector is based on both SAE J560 and ISO 1185 and is providing either 12V, 7 x 40A or 24V, 7 x 20A. The voltage varies from vehicle to vehicle.

There are two basic types of electrical plug and socket connectors for light trailer use - one is round and the other flat. The 7 pin flat connector is generally more robust than its round 7 pin cousin, which being round - may be damaged or pulled out easier. Flat plug and sockets are also known as Type 3 connectors and come in 7 pin and 12 pin.

As mentioned earlier for 7 pin connectors, if interchangeability problems arise, then it is recommended that pin number 5 in the 7 pin connectors be used only for service brakes, although if auxiliary circuits are required, then the 12 pin Type 3 connector would be preferable.

• Pin 1 - Yellow - Left-hand turn indicator


• Pin 2 - Black - Reversing signal


• Pin 3 - White - Earth return


• Pin 4 - Green - Right-hand turn indicator


• Pin 5 - Blue - Service brakes


• Pin 6 - Red - Stop lamps


• Pin 7 - Brown - Rear lamps, clearance and side marker lamps

The 12 pin Type 3 connector plug and socket is basically an extension of the 7 pin. 12 pin connectors are available, but may need to be ordered since some shops don't stock them. Aside from the extra wires for fog lights, accessories, winch power etc, the extra row are larger pins and there is also a 2nd earth pin. Again, if auxiliary circuits are required such as the ones listed above, then the 12 pin Type 3 connector would be preferable over the 7 pin version.

• Pin 1 - Yellow - Left-hand turn indicator


• Pin 2 - Black - Reversing signal


• Pin 3 - White - Earth return


• Pin 4 - Green - Right-hand turn indicator


• Pin 5 - Blue - Service brakes


• Pin 6 - Red - Stop lamps


• Pin 7 - Brown - Rear lamps, clearance and side marker lamps


• Pin 8 - Orange - Battery charger/electric winch


• Pin 9 - Pink - Auxiliaries, etc/battery feed


• Pin 10 - White - Earth return


• Pin 11 - Grey - Rear fog lamp


• Pin 12 - Violet - Spare