I recently got a new Edge 810 and was paring the sensors - Power Meter, HR Monitor, Phone all without issue. I have a speed sensor that I use when riding on the trainer but I could not get the Edge to recognize it. The Speed Sensor is about a year old so I thought it could be the battery. Replaced the battery and the indicator light flashed green - red - green to indicate it was activated. I attached it to the hub and when I rotated the wheel to see if the sensor was transmitting the green indicator light never flashed and the Edge never recognized it. Repeated the process but still no dice.
The installation process couldn't be simpler but if I'm missing something please enlighten me