Have problem with your Garmin Cadence sensor 2? Check this out.. 

I bought Garmin edge bundle with speed and cadence sensor included. When I install it, my edge detect 2 sensors but both are recognized as speed sensors.. one is connected through ANT+ and the other is through BLE.. then after awhile, I just realize that my cadence sensor doesn’t have any blinks.. that’s why the cadence data is not there... so then I open the battery compartment and found out, that the battery is not connected correctly.. this is due to wrong placement at how they put battery conductor/sticker in its case... a simple manufacture mistakes that can make you feel confused and mad...
no worries, this is how I fix the issue, and everything is ok now.. I’m sorry I didn’t take a long shot video during the process, but hopefully this will simply explain how...
cheers..!!!