Trailers · Connector reference
24N, 24S and ISO 12098 15-pin trailer connectors
European 24 V trucks and trailers connect their lighting through either a pair of 7-pin connectors, 24N and 24S, or a single 15-pin connector. Here is what each carries, and what to check before wiring an adapter between them.
Three connectors, one job
| Connector | Standard | Housing | Carries |
|---|---|---|---|
| 24N ("normal") | ISO 1185 | Black | Basic lighting and the trailer brake control signal |
| 24S ("supplementary") | ISO 3731 | White | Functions the 24N cannot carry, such as reversing and rear fog lamps and permanent power |
| 15-pin | ISO 12098 | — | The functions of both 7-pin connectors in one plug, plus a CAN data pair |
The editions cited by connector maker Erich Jaeger are ISO 1185:2003, ISO 3731:2003 and ISO 12098:2020. The two 7-pin connectors use different housing colors and contact layouts so that a 24N plug cannot be pushed into a 24S socket. None of these connectors carry the trailer's ABS or EBS; that has its own connector under ISO 7638 (see ISO 7638 ABS/EBS connector).
12 V vehicles have their own equivalents. The 12 V type N 7-pin connector is ISO 1724, and the 13-pin connector common on European cars and light trailers is ISO 11446. Do not mix 12 V and 24 V parts.
24N contact allocation (ISO 1185)
| Contact | Function | Cross-section | Color | DIN 72552 |
|---|---|---|---|---|
| 1 | Common return | 2.5 mm² | White | 31 |
| 2 | Left rear position and marker lamps | 1.5 mm² | Black | 58L |
| 3 | Left direction indicator | 1.5 mm² | Yellow | L |
| 4 | Stop lamps | 1.5 mm² | Red | 54 |
| 5 | Right direction indicator | 1.5 mm² | Green | R |
| 6 | Right rear position and marker lamps | 1.5 mm² | Brown | 58R |
| 7 | Trailer brake control | 1.5 mm² | Blue | — |
24S contact allocation (ISO 3731)
| Contact | Function | Cross-section | Color | DIN 72552 |
|---|---|---|---|---|
| 1 | Common return | 2.5 mm² | White | 31 |
| 2 | Reserved (see note) | 1.5 mm² | Black | — |
| 3 | Reversing lamp | 1.5 mm² | Yellow | — |
| 4 | Permanent power supply | 2.5 mm² | Red | 30 |
| 5 | Sensing device with common return | 1.5 mm² | Green | — |
| 6 | Power supply controlled by ignition | 2.5 mm² | Brown | 15 |
| 7 | Rear fog lamp | 1.5 mm² | Blue | — |
Note on contact 2: Erich Jaeger lists contact 2 as reserved in the current edition. Some published diagrams show it used for an ABS fault indication. Check the actual vehicle before relying on either.
15-pin contact allocation (ISO 12098)
| Contact | Function | Cross-section | Color |
|---|---|---|---|
| 1 | Left direction indicator | 1.5 mm² | Yellow |
| 2 | Right direction indicator | 1.5 mm² | Green |
| 3 | Rear fog lamp | 1.5 mm² | Blue |
| 4 | Common return | 2.5 mm² | White |
| 5 | Left rear position and marker lamps, license plate lamp | 1.5 mm² | Black |
| 6 | Right rear position and marker lamps, license plate lamp | 1.5 mm² | Brown |
| 7 | Stop lamps | 1.5 mm² | Red |
| 8 | Reversing lamp | 1.5 mm² | Pink |
| 9 | Continuous power supply | 2.5 mm² | Orange |
| 10 | Reverse lock / steering axle locking (see note) | 1.5 mm² | Gray |
| 11 | Starting-traction control (see note) | 1.5 mm² | White/black |
| 12 | Axle lifting device | 1.5 mm² | White/blue |
| 13 | Common return for data lines | 2.5 mm² | White/red |
| 14 | CAN-H | 1.5 mm² | White/green |
| 15 | CAN-L | 1.5 mm² | White/brown |
Note on contacts 10 and 11: the table follows Erich Jaeger's summary of ISO 12098:2020. Other published diagrams assign these two contacts to brake lining wear and spring brake indication. Auxiliary contacts are where different editions and vehicle makers diverge, so confirm them against the tractor and trailer documentation. The CAN pair on contacts 14 and 15 follows ISO 11992-3 and is for equipment other than the braking system and running gear.
Adapters between 15-pin and 2 × 7-pin
Mixed fleets use adapter cables: a 15-pin plug to two 7-pin sockets, or the reverse. Reading the tables above side by side shows why these need care:
- The same function sits on different contacts. Stop lamps are contact 4 on a 24N and contact 7 on the 15-pin. Direction indicators move from 3 and 5 to 1 and 2.
- Some functions have no counterpart. The 15-pin CAN pair and axle functions have nowhere to go on a 24N/24S pair, and the 24N brake control contact has no dedicated 15-pin contact.
- Returns must be sized for the combined load. Use the 2.5 mm² conductors for common returns and power feeds as the tables show.
- Test every function end to end after building or buying an adapter, with both vehicle types.
Reading European wiring diagrams
European trailer diagrams often label circuits with DIN 72552 terminal numbers rather than names, which is why the 24N and 24S tables above include them. The ones you will meet most often:
- 31: ground (return);
- 30: permanent battery positive;
- 15: positive switched by the ignition;
- 54: stop lamps;
- 58L / 58R: left and right position lamps;
- L / R: left and right direction indicators.
When a diagram, a tractor maker's manual and a connector label disagree, the terminal number is often the quickest way to establish what a conductor is meant to do.
Common questions
Which connector do new European trucks use?
New heavy vehicles increasingly use the 15-pin ISO 12098 connector, and Erich Jaeger describes the 24S system as being progressively replaced by it. Older equipment still uses 24N and 24S, which is why adapters are common.
Why are the 24N and 24S housings different colors?
The black 24N and white 24S look similar but carry different functions. The color and the contact arrangement stop a plug going into the wrong socket.
Do these connectors carry ABS or EBS?
No. The trailer braking system uses the separate ISO 7638 connector.
Is the 15-pin CAN link the same as the brake CAN link?
No. The ISO 12098 data pair is for equipment other than braking systems. The brake data link is on ISO 7638 contacts 6 and 7.
What to send a supplier
- Connector standards and genders at each end, and whether an adapter must be fully wired or lighting only.
- The contact-to-contact wiring table you want, including auxiliary contacts, in writing.
- Cable cross-sections per circuit, coiled or straight, and working length.
- Test requirement: function-by-function verification on every part.
For the harness these connectors feed, see trailer wiring harnesses.
Last reviewed 2026-09-17