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How does the backlight of my Suunto watch work?

This article applies for: see list of devices below under Find more support for. Here are some tips for setting the right watch display brightness and troubleshooting steps if the backlight seems to work incorrectly.


1. Toggle vs. Automatic mode

The backlight of your Suunto watch offers two modes: Toggle and Automatic. We recommend using the default mode Automatic. Find a detailed explanation of both modes in the user guide for your watch under Features > Backlight. Go to the user guide.

2. Adjust display brightness - Spartans and Suunto 9 only

To increase or decrease the display brightness level on your Spartan or Suunto 9 open Settings > General > Backlight > Brightness and adjust the brightness level.

Note: This functionality is not available for Spartan Trainer, Suunto 3 Fitness and Suunto 5.
Note: Backlight brightness affects battery life. The brighter the backlight is, the quicker the battery drains.

3. Optimize display readability during exercise

In addition to adjusting the display brightness, each sport mode allows you to define specific display settings in the Options menu below the exercise start screen. To optimize the display readability,

  • Toggle Backlight to on
  • Adjust the display Theme to be black or white


Troubleshooting steps
1. Deactivate Do not disturb mode

The Do not disturb mode will dim the watch display on Spartan watches with software version 2.5.20 or later, Suunto 9, Suunto 3 Fitness and Suunto 5 watches.

To deactivate the mode and adjust the display brightness:

  1. Go to the watch face.
  2. Long press the middle button to open the Shortcuts menu.
  3. Toggle off Do not disturb mode (toggle is grey).
2. Deactivate power-saving mode

When the power-saving mode is active, your watch dims the display to save battery. To deactivate the mode, open mode Settings > General and toggle off Power saving (toggle is grey).

3. Ensure you have the latest software installed on your watch

We continuously improve the software of our watches and fix bugs that we see in the field. Connect your watch with your Suunto cable to your computer with SuuntoLink installed and check if a software update is available for your watch.

Don't know how to update your watch? Watch this video.


If the watch display is frozen or blank but the backlight is on and the watch reacts with vibration to button presses: Soft reset your watch. Learn more. If none of the mentioned tips or troubleshooting steps helped you solve the issue, please contact our customer support team. We are happy to assist you.