We are troubleshooting an issue with backlight settings that some users have experienced with the 7.60 update. We apologize for the inconvenience, I understand how frustrating this can be. We are developing a permanent fix for this issue, please keep an eye out for beta software updates (which will be posted here on the forums.)
In the meantime, we have a file you can install on your watch that will fix the backlight function. I've attached the file to this post. If you'd like to install it, plug your device in to the computer. Open the "Garmin" folder, then open the "NewFiles" folder. Put the attached "backlight_mode_fix.fit" file inside the "NewFiles" folder. Now unplug your device from the computer and you should be able to reconfigure your backlight to the proper settings
There is a possibility that future syncs with Garmin Connect will again send incorrect backlight settings to your watch. Again, we are working as fast as we can to completely resolve that problem. If you find that installing the attached file is only a temporary solution, my recommendation would be to remove your watch from your Garmin Connect account (and Garmin Express if you use that.) Then, after using the fix file and restoring your backlight settings, you can re-add your device to your account. If you follow these steps, you will not lose any data from your account. But it should “reset” the data that Garmin Connect could be sending you, and your backlight should stay functional.
If, worst case scenario, removing the device from your account and using this file still doesn't work, the next step would be a factory reset on the device and then re-adding it to your account. (1. Remove from account. 2. Install fix file. 3. Factory reset. 4. Reconnect to account.) If you'd prefer to bear with the bug for just a few more days and avoid a factory reset, we hope to have a software fix available within the beta update available sometime next week.
In the meantime, we have a file you can install on your watch that will fix the backlight function. I've attached the file to this post. If you'd like to install it, plug your device in to the computer. Open the "Garmin" folder, then open the "NewFiles" folder. Put the attached "backlight_mode_fix.fit" file inside the "NewFiles" folder. Now unplug your device from the computer and you should be able to reconfigure your backlight to the proper settings
Given the last response for this was 2 years ago and this thread is for the Fenix 5 series, I would suggest you post your issue on the appropriate sub forum https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-735xt .Pretty sure if the file for the fix was still available here it would not work on your watch anyway.
