I just bought the new Garmin speed and cadence sensors. It initially paired with my 620 but would only pick up speed and not cadence. I tried to re-pair it and keep getting this message "rotate the wheel to activate the sensor and try again". I have rotated the wheel, restarted my 620 and still won't pair. Any ideas I can try?
Obvious first thing to try is a replacement battery in the sensor - I know it's new but it is not beyond possible that the battery had a manufacturing defect or that it was sat on the shelf long enough to go flat...
