Troubleshooting - Check Relay Operation

Verify Relay 'Trigger Input' Voltages

Using a digital multimeter VOM, measure the voltage on the IN3 & IN4 trigger input wires.

  • When the brake is applied, +12vdc should be applied at both IN3 and IN4.

If the voltages are present and the relays don't trigger, then the relay module is bad and should be replaced.




Troubleshoot the brake circuit wiring.

If the voltages are not present, there may be an open or short circuit in the 12vdc brake circuit. 

Refer to 12v accessory wiring diagram to troubleshoot.

Before removing the relay module, turn off all the power on the e-bike and make careful notes regarding all the wire colors and connection points. I usually take a photo to back that up. A replacement relay module is available in our parts shop