Connecting trailer lights: how does it work?

Connecting the lights on your trailer correctly? The pin configuration and different types of connections, such as the 7-pin and 13-pin plug, are especially important. We will show you exactly how this works using the trailer wiring diagram.

In this blog you will find:  

• A clear explanation using the various wiring diagrams
• Step-by-step instructions for safe and efficient installation of trailer lights

Connecting trailer lighting - with a 7-PIN connector

The illustration below shows the 7-PIN connector wiring diagram. This illustration shows all seven different functions.

Trailer lighting wiring diagram 7-PIN connector/socket universal 12 Volt.

1. Connection/Pole 1 (colour: yellow): Direction indicator left;
2. Connection/Pole 2 (colour: blue/brown): Rear fog light;
3. Connection/Pole 3 (colour: white): Mass (serving contacts 1 to 7);
4. Connection/Pole 4 (colour: green): Direction indicator right;
5. Connection/Pole 5: (colour brown): Rear light/side marker light and number plate right;
6. Connection/Pole 6: (colour red): Brake lights;
7. Connection/Pole 7: (colour black): Rear light/side marker lights left.

As the name suggests, the 7-PIN connector consists of seven different connections. In the illustration below, these connections are indicated by different colours. Using these colours, combined with the information below, you can easily connect your trailer's lighting.

Difference between 7-PIN and 13-PIN connector

In the trailer lighting market, we know three types of wiring diagrams, namely the wiring diagram for the 7-Pin connector, the 13-Pin Jaeger plug and the 13-Pin Multicon plug. Before we continue on this subject, it is important to briefly explain the distinction between the 7-PIN and the 13-pin junction box.

The difference between the two plugs is that the 13-pole connector has more connections (and therefore functionalities). A 7-PIN connector only provides the vehicle with basic lighting, such as indicators and brake lights. The 13-pole connector, on the other hand, powers the vehicle's multiple functions.

Connecting 7-PIN connector

The 7-PIN connector variant is suitable for less complex towing objects, such as bicycle carriers, trailers, boat trailers or horse trailers. Using the 7-PIN connector, it is possible to connect the basic lighting to your towing object. Here, you can think of the basic lighting within the category of LED rear lights (fog lights, indicators and brake lights). Even though the 13-pin connector is more extensive, the 13-PIN connector still fully complies with the set standards.

Connecting 13-PIN connector

This variant connector can be seen as the big brother of the 7-PIN connector. The 13-pole connector is intended for more complex towing objects. For example, a caravan, advanced trailer, large boat trailer or large horse trailer. Just like the 7-PIN connector variant, this plug is also connected to your car. You can connect it to the trailer by plugging the connector into the coupling under the tow bar.

The extra poles on a 13-PIN connector are used for reversing lights, as an extra constant current and as a switching current with mass, among other things. This extra constant current can be used, for example, for your caravan's refrigerator, charging your battery or electrically opening and closing your trailer body. If you need any of these functions, we strongly recommend choosing the 13-PIN connector over the 7-PIN connector.

Connecting trailer lighting - with a 13-PIN connector:

For the 13-PIN connector trailer scheme, see the illustration below. This illustration describes all thirteen functions of the Jaeger plug. Using this wiring diagram, you can connect the lighting to the trailer.

Trailer lighting wiring diagram, 13-PIN connector/socket universal 12 Volt.

Connecting a 13-PIN connector is very easy using the wiring diagram above. As shown in the picture, this junction box consists of thirteen different connections. As above, we will also explain the different plugs from the junction box with 13-pole connector below. For the visual thinker, we have also added an image to outline the complete picture in one overview. Using this scheme, you can correctly connect the lighting on the trailer.

Thirteen connections 13-PIN connector (Jaeger)

1. Connection/Pole 1 (colour: yellow): Direction indicator left;
2. Connection/Pole 2 (colour: blue): Rear fog light;
3. Connection/Pole 3 (colour: white): Mass (serving contacts 1 to 8);
4. Connection/Pole 4 (colour: green): Direction indicator right;
5. Connection/Pole 5: (colour brown): Rear light/side marker light and number plate right;
6. Connection/Pole 6: (colour red): Brake lights;
7. Connection/Pole 7: (colour black): Rear light/side marker lights left;
8. Connection/Pole 8: (colour grey): Reversing lights;
9. Connection/Pole 9: (colour brown/blue): Permanent interior lighting power wire;
10. Connection/Pole 10: (colour brown/red): Charging cable for caravan battery/refrigerator;
11. Connection/Pole 11: (colour white/red): No destination (possibly mass);
12. Connection/Pole 12: (-): No destination;
13. Connection/Pole 13: (black/white): Mass (serving contacts 9 to 12).

Connecting trailer lighting using a 13-PIN Multicon West connector:

The illustration below shows all thirteen functions of the Multicon West connector. Using this scheme, you can properly connect the lighting to the trailer.

Thirteen connections 13-PIN connector (Multicon West)

1. Connection/Pole 1 (colour: yellow): Direction indicator left;
2. Connection/Pole 2/54G (colour: blue): Rear fog light;
3. Connection/Pole 3/31 (colour: white): Mass (serving contacts 1 to 8);
4. Connection/Pole 4/R (colour: green): Direction indicator right;
5. Connection/Pole 5/58R: (colour brown): Rear light/side marker light and number plate right;
6. Connection/Pole 6/54: (colour red): Brake lights;
7. Connection/Pole 7/68L: (colour black): Rear light/side marker lights left;
8. Connection/Pole 8: (colour grey): Reversing lights;
9. Connection/Pole 9: (colour brown/blue): Permanent interior lighting power wire;
10. Connection/Pole 10: (colour brown/red): Charging cable for caravan battery/refrigerator;
11. Connection/Pole 11: (colour white/red): No destination (possibly mass);
12. Connection/Pole 12: (-): (possibly work lights);
13. Connection/Pole 13: (black/white): Mass (serving contacts 9 to 12).

The difference between the 13-pin Jaeger plug and the 13-pin Multicon connector

Within the 13-PIN connectors, there are two different systems, namely the Jaeger and Multicon West system. When connecting a 13-PIN connector, it is good to know that the two plugs have different poles. For this reason, we briefly light both connectors below.

Jaeger 13-PIN connector

The new 'standard' plug is the Jaeger plug. This connector has a bayonet connection. This ensures that the connector is firmly attached to the junction box and will not vibrate loose while driving. The bayonet connection is a valued connection, as it significantly reduces interference while driving.

Connecting the 13-pole Jaeger plug is very easy. Insert the Jaeger plug into the junction box at a 90-degree angle to the left. In this situation, the mounting block protrudes downwards. When it is in the junction box, turn the connector a quarter turn clockwise. Then turn it into the junction box and the bayonet connection is fixed. If you want to connect the Jaeger plug with 13 poles to a 7-PIN connector, this is possible with an adapter.

Multicon West 7/13-pin connector

Besides the 'standard' 13-PIN connector, there is also another model called the Multicon West connector. This plug fits both the 7-pin and the 13-PIN connector. This makes the Multicon system usable as a 7-PIN and 13-PIN solution. This Multicon plug can come in handy if your trailer still uses an old 7-PIN connector.

However, it is worth noting that the Multicon plug does not fit into a Jaeger plug box, and vice versa. Looking at the use of both plugs, it is striking that the Jaeger plugs are used more often than the Multicon West plugs. In turn, the Multicon West system is more common in caravans.

Various adapter plugs for connecting junction boxes

Most vehicles today contain a 13-PIN junction box, while most 12V trailers and bike carriers tend to have a 13-PIN connector. To ensure that these can be connected together flawlessly, use an adapter plug. Adapter plugs come in different types. Below, we briefly lighten the different adapter plugs in our range.

adapter from 13 to 7-PIN

The adapter that converts a 13-PIN connector to a 7-PIN connector functions opposite to the situation described above. If your vehicle is equipped with a 13-PIN connection, this adapter allows you to connect a 13-PIN connector. However, it is important to realise that in this case, only the functionalities associated with a 7-PIN connection will be active.

adapter from 7 to 13-PIN

The 7-pin to 13-pin adapter allows you to connect almost any electronic product to your vehicle's connector. If, for example, you have a 13-PIN caravan connection but a 7-PIN junction box, you can convert it with the adapter. In short, the sales adapter from 7-pin to 13-pin connector is meant to allow you to use a 13-pin connector, when your car is only equipped with a 7-PIN connector.

You can find the matching product on our dealer portal via the following left: Adapter adapter from 7 to 13-PIN.

Frequently asked questions on 7-PIN and 13-PIN connectors

At TRALERT® we regularly receive questions about the 7-PIN and 13-PIN junction boxes. Below we have therefore listed these frequently asked questions for you.

When do I use a 7-PIN connector?

A 7-PIN connector only provides the basic lighting. This includes indicators and brake lights. A 7-PIN connector is perfectly suitable for cycle carriers or small trailers, for example.

When do I use a 13-PIN connector?

The extra poles of a 13-pole connector are used when, in addition to the basic lighting, you also use reversing lights and the rear fog light, among other things. These two options have been mandatory on trailers, caravans, boat trailers and/or horse trailers since 10 July 2011. Since 2011, these vehicles have therefore been equipped with a 13-pole junction box as standard.

What types of 13-PIN connectors are there?

The 13-PIN connector variant has two types, namely the Jaeger and the Multicon West plug. These are used for different purposes. Of the two, the Jaeger junction box is the most common. Although the Multicon West is most often used with caravans.

More questions about the various junction boxes or connecting trailer lighting?

Is your question not listed above and are you looking for a suitable answer? Then feel free to contact our technical experts. They will be happy to answer all your questions about trailer lighting, the wiring diagram for trailers and the various connections involved.

Want to know about regulations? Then read the article on trailer lighting regulations.

The TRALERT® choice

If you are looking for lighting for your trailer, we recommend this complete set from TRALERT®. The set includes rear lights, marker lights, licence plate lights and side marker lights, allowing you not only to hit the road safely, but also stylishly with our careful selection.

Better Light Work Safer!