just got a macro gps and made the mistake of pairing the speed sensor first. Had to disconnect it and then pair with the cadence+speed sensor to get both. Something to check -- only have to pair the combo sensor; pairing it with one or the other will get in the way. To rephrase: if you paired the gps with your sensor as the speed or cadence by itself, it won't pair as the combo. And in the 'is it plugged in' category -- spin the pedals to wake up the sensor? --Does the sensor pair with strava or mapmyride etc?