Nest thermostat display is very dim or backlight does not turn on

Safety: No high‑voltage work is required.

• Adjust brightness: In the Nest settings, increase display brightness and disable any power‑saving display options temporarily.
• Test in dark room: Cover the Nest with your hand to simulate darkness and see if the display brightens.
• Restart thermostat: Restart the Nest to clear any temporary sensor glitches.
• Check power stability: Ensure R and C are properly connected and that there are no power errors reported.
• Replace thermostat: If the display remains dim or off despite correct settings and power, the backlight or display driver has likely failed and the Nest should be replaced.