F20 / F20 Pro Wiring Diagram Guide (Old S866 & New 81-C Version Explained)

Whether you are replacing a controller, diagnosing electrical problems, or upgrading your F20 series e-bike, understanding the controller wiring layout is extremely important. In this guide, we will explain the controller wiring diagram and cable functions for the FAFREES F20 series, including the F20, F20 Pro Old Version (S866), and F20 Pro New Version (81-C).

In the following sections, we will provide important installation notes to help you safely replace, or upgrade your bike components.

Controller Cables

1. Throttle cable (black-yellow-red)

2. Brake power cable (black-red)

3. Motor cable (blue-green-yellow-red-white-black)

4. Front light cable (yellow-black-green)

5. Display cable(yellow-green-black-blue-red)

6. Pedal sensor cable (black-red-blue)

7. Motor phase cable (yellow-green-blue)

8. Power cable (black-red)

9. Programmer cable