First, please make sure that you are using fresh batteries in both units as well as the included power adapter, then perform the following reset. Please follow the steps carefully as the order is crucial to the success of the reset.
Hard Reset:
1. Bring both the sensor and display unit together and remove batteries from the outdoor sensor. Make sure that the Wireless Reception Indicator on the display drops to zero bars to ensure that your display was connected to the correct sensor. (If your wireless reception indicator already indicates zero bars, please proceed to Step #2.)
NOTE: If your display unit continues to show a strong connection, there is another sensor in your area that your display is connecting to (either a neighbor's or from another of your AcuRite units).
2. Remove the batteries and/or power adapter from the display unit.
3. Reinstall the batteries in the outdoor sensor.
4. Once the batteries are inserted you should see the red LED light blink approx. every 30 seconds on the front of the sensor. The red LED light should NOT stay on continuously.
5. Reinstall batteries and/or power cord into the display unit.
6. Let the units sit within a couple of feet of each other for approximately 5 minutes or until you see a solid sensor signal.