How you re-pair a remote sensor to my thermostat system?
All you need to do to pair or re-pair a remote sensor with the thermostat is remove the tab on the back part of the sensor while standing in front of the thermostat.
If there is no plastic tab on the back of the sensor, please perform the following steps while standing in front of the thermostat:
1. Remove the circular backing from the back of the sensor.
2. Remove the battery from the battery slot.
3. Gently lift the prongs in the middle of the battery slot with your index fingernail.
4. Place the battery back into the battery slot with the positive side facing down for 30 secs.
5. Remove the battery and place the battery back in with the positive side facing up.
6. Place the backing back onto the battery slot.
A message should appear on the thermostat screen asking you to pair the remote sensor with the thermostat. Follow prompts from thermostat.
Refer to this article for more information: https://ecobee.zendesk.com/hc/en-us/articles/227874847-Step-6-Activating-Remote-Sensors-Installation-Trouble-shooting