I have just changed the battery in my garmin cadence sensor on my road bike, but when I press the reset button only the red light shows but no green light. Anyone know why? Thanks

  • Did you fit a flat/dead/wrong battery?
    – Criggie
    Oct 31, 2016 at 21:17
  • 1
    good points @Criggie. Also make sure positive and negative contact points are not reversed.
    – Nikolai
    Oct 31, 2016 at 21:21
  • Sounds to me like they need re-pairing because they are wireless?
    – Criggie
    Jan 24, 2017 at 6:53

1 Answer 1


The red light flashes when the magnet passes the pick up sensor that you attach to the frame. The same sensor has an adjustable "arm" on it to pick up the magnet mounted on a spoke. It should flash green if it senses the magnet as it goes past the sensor arm. My experience is either the arm and or the entire sensor needs to be adjusted.
Good luck.

  • Welcome to Bicycles @Paul. Thanks for answering one of our questions. We recommend all new members take the tour to make best use of the site, and since you're answering How to Answer will be helpful also. Again, welcome
    – andy256
    Jan 24, 2017 at 4:37
  • the newer garmin cadence sensors do not use a seperate magnet
    – Mark W
    Jan 24, 2017 at 8:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.