Trailer Connector Wiring Diagram - 4-Pin Flat, 6-Pin Round & 7-Blade Pinouts

This document is a trailer wiring connector reference chart showing pinouts and wire color codes for three common trailer connector types. The first diagram covers the 4-Pin Flat Plug, showing both plug and socket views with four circuits: Ground (White), Left turn (Yellow), Markers (Brown), and Right turn (Green). The second diagram illustrates the 6-Pin Round connector, viewed as plug back / socket front, adding two circuits to the four-pin layout: Accessory and Brake (Black), alongside Markers (Brown), Ground (White), Left (Yellow), and Right (Green). The third diagram shows the 7-Blade Round connector, also viewed as plug back / socket front, with blades numbered 1 through 7 arranged around a central pin. Its legend lists: 1 (White) Ground, 2 (Blue) Brake, 3 (Green) Markers, 4 (Black) Battery, 5 (Red) Left, 6 (Brown) Right, and 7 (Yellow) Reverse. A reader can use this chart to identify the correct wire color and pin position for each trailer lighting and brake circuit when wiring or troubleshooting 4-pin, 6-pin, or 7-blade trailer connectors on a tow vehicle or trailer.