If your Mac keyboard, mouse or trackpad indicator light is flashing
When your Apple wireless keyboard, mouse or trackpad is turned on, the indicator light flashes twice in succession, pauses, then repeats (blink-blink-pause, blink-blink-pause). This means the keyboard, mouse or trackpad is “discoverable” by your Mac, and you can connect your Mac with it. After 3 minutes, the indicator light turns off. The keyboard, mouse or trackpad is still on, but it is no longer discoverable. To make it discoverable again, turn it off, then turn it back on.
When the wireless keyboard, mouse or trackpad connects with your Mac, the indicator light illuminates steadily for 3 seconds before it turns off. This indicates that the device has successfully connected with your Mac.
While your Apple Magic Mouse is connected to your Mac, the indicator light blinks at regular intervals. It might blink fast or slow, but in all cases, a regular blinking pattern means the mouse is connected to your Mac and is operating properly. The indicator light on an Apple wireless keyboard doesn’t blink.