According to the manual the red LED blinks each time the pedal magnet passes the sensor. The green LED blinks each time the spoke magnet passes the sensor arm. The speed will show when the "crank" icon appears on the main screen. I found the cadence (red LED) works only if the timer is started. Try moving the magnet around until the icon shows up.
www.texbiker.net Texas Bicycling News, Events, Experiences