ISO 3732
- Updated:
- By: Kevin van Mierlo
Contents
ISO 3732 - The standard behind the 7-PIN connector (12V).
ISO 3732 is the international standard that defines the 7-PIN S-connector. This 12V connection was previously used in conjunction with the 7-PIN N-connector to enable additional functions on trailers and caravans. Examples include a constant power supply, battery charging and reversing lights.
Whereas the N connector was responsible for basic lighting, the S connector provided the additional functions. In the current market, this system has largely been replaced by the 13-PIN connector according to ISO 11446, in which all functions are combined in one waterproof plug connection.
Wiring diagram 7-PIN connector according to ISO 3732
| PIN | Function | Colour |
|---|---|---|
| 1 | Battery charging current | Grey |
| 2 | Free (optional) | Black |
| 3 | Mass for PIN 1 | White |
| 4 | Free (optional) | Green |
| 5 | Reversing lights | Blue |
| 6 | Mass for PIN 2 (constant +) | White |
| 7 | Constant power supply | Red |
Please note that the functions on the PINs of an S connector are completely different from those on an N connector. Incorrect connection can lead to damage or interference.
Where do we come across ISO 3732 connectors?
The ISO 3732 S connector was mainly used in:
- Older caravans with refrigerator, lighting or battery charger
- Towed vehicles with reversing lights
- Motorhomes with separate circuits for lighting and power supply
In many cases, you will still come across this system on vehicles predating the introduction of ISO 11446.
ISO 3732 and the future
New vehicles and trailers almost exclusively use the 13-PIN Jaeger connector (ISO 11446). This provides a safer, waterproof connection and combines the functions of both the N and S connectors.
TRALERT® recommends choosing ISO 11446 for replacement or new installations. This simplifies connection and avoids confusion about pin functions.
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Author
Kevin van Mierlo
Lighting expert at TRALERT® - Kevin tests lighting and finds out everything about legislation. He can tell you all about it.
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