To work the light, please follow these instructions.
•    Step One: Press the LIGHT button (top left hand side of the watch.)  Check to see if the screen is illuminated.  Cover the face of the watch or test in a dark area as the backlight may not be easily visible in well-lit environments.
•    Step Two: If the backlight does not go on by following step one, press and hold the STOP button (bottom right hand side of the watch.)  The display on the watch’s face will read HOLD and the watch will beep (takes approx. 2 seconds.)  This will activate the light function on some MIO models (not applicable to all.)  Then repeat step one to use the light.
•    If you cannot get your light to work, this could be an indicator of a weak battery.
•    Note:  For the MIO Ultimate – press and hold the OPTION button to activate the light.

Please view MIO's interactive Demo to see a visual guide for this feature. 

Please note that the light is not a constant backlight display.  The watch is only illuminated for a few seconds at a time.  The light works this way in order to preserve the life of the battery.