ISO 1724 (7-Pin) vs. US 4-Pin Flat Connector
Comparing 2 standards across 14 specifications. 14 key differences identified.
The ISO 1724 Connector (commonly known as the European Type 12N 7-Pin plug) is the classical European standard for basic trailer lighting. Featuring a circular 7-pin metal or plastic housing with split brass pins, it provides the essential exterior road lighting circuits (left/right turn, isolated left/right tail lights, brake lights, and rear fog lamp).
The US 4-Pin Flat Connector (standardized under SAE J1239) is the ubiquitous North American electrical plug for light-duty utility trailers, small boat trailers, and snowmobile haulers without electric brakes. Utilizing an inline rubber molded connector with one exposed male pin and three shrouded female sockets.
Specification Comparison Table
14 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standardization
|
ISO 1724 / DIN 72577 (Type 12N–Normal) | SAE J1239 / 4-Pole Flat Connector |
|
Pin 1 (Yellow–Terminal L)
|
Left Hand Direction Indicator (Turn signal) | — |
|
Pin 2 (Blue–Terminal 54G)
|
Rear Fog Lamp (or +12V permanent feed on older caravans) | — |
|
Pin 3 (White–Terminal 31)
|
Common Chassis Ground Return | — |
|
Pin 4 (Green–Terminal R)
|
Right Hand Direction Indicator | — |
|
Pin 5 (Brown–Terminal 58R)
|
Right Hand Tail Light, Clearance Lights, and License Plate Lamp | — |
|
Pin 6 (Red–Terminal 54)
|
Brake / Stop Lights | — |
|
Pin 7 (Black–Terminal 58L)
|
Left Hand Tail Light and Left Hand Clearance Lights | — |
|
Pin 1 (White–Exposed Male Pin)
|
— | Ground / Earth Return (Exposed male pin ensures ground connects first upon insertion) |
|
Pin 2 (Brown–Shrouded Female)
|
— | Tail Lights, License Plate Lamp, and Side Marker Running Lights |
|
Pin 3 (Yellow–Shrouded Female)
|
— | Left Turn Signal and Left Stop/Brake Light |
|
Pin 4 (Green–Shrouded Female)
|
— | Right Turn Signal and Right Stop/Brake Light |
|
Combined Stop/Turn Architecture
|
— | Brake and turn signals share the same wire and bulb filament (flashing one filament while braking) |
|
5-Pin Flat Extension
|
— | Adds a 5th Blue wire for Reverse Lights / Surge Brake Hydraulic Lockout Solenoid (boat trailers) |