If the outdoor temperature is showing dashes or not changing the units may have lost connection or are experiencing interference. 

1. Verify that the A-B-C switch in the battery compartments of both the display and sensor are set to the same letter. You may choose A, B, or C; but both units must match to sync up.
2. Relocate the display unit and/or the outdoor sensor. Under optimal conditions, the units can be located up to 330 ft (100 m) of each other.
3. Units should be placed at least 3 feet (.9 m) away from electronics that may interfere with wireless communication (such as TVs, microwaves, computers, etc).
4. Ensure that you are using recommended batteries:

• Verify you are using fresh batteries in the sensor. Lithium batteries are recommended for installation locations where temperatures can go below -4°F/-20°C.
• Verify you are using batteries with a nominal voltage of 1.5 volts.          
  NOTE: Some rechargeable batteries carry low or inconsistent voltages that may not properly power the device.  
• Mixing different battery types (brands, old/new, etc.) is not recommended.

Synchronize the units:

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. Change A-B-C switch on both units to a new matching A-B-C channel then press and hold the reset button on the display for 20 seconds.
3. Reinstall the batteries in the outdoor sensor.
4. Once the batteries are inserted you should see the red LED light blink approx. every 18 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 then immediately press and hold the reset button again for 20 seconds.
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.

If you are still experiencing concerns, please contact our U.S. based support staff by Submitting a Request or by chatting with our Live Agents. If you already have an open ticket with a support agent, please reply to the last email sent.