Thermostat backlight very dim or flickering but unit otherwise works

Safety first: If opening the unit, isolate power first.

Steps:

• 1. Check brightness setting: In the display settings, increase brightness and disable aggressive power saving.
• 2. Verify supply voltage: Ensure the thermostat is receiving correct voltage at the backplate.
• 3. Acceptable ageing: If the thermostat is several years old and only the backlight is affected, you may choose to continue using it if the display is still readable.
• 4. Replace thermostat: Backlight LEDs and drivers are not user‑replaceable; replace the thermostat if visibility is poor.