Your door/window sensor has two parts: the sensor and a magnet. If your door is closed but the sensor is showing that it is open, this usually means the sensor and the magnet are out of alignment. To check this, follow the steps below.
- Locate the sensor and magnet. Normally, the magnet is located on the door or window frame, close to the sensor.
- If the magnet has fallen off, you can reattach it with double-sided sticky tape.
- Make sure the gap between the sensor and the magnet is no more than ¼ inch, and the magnet is directly across from the guidelines on the side of the sensor.