Thermostat display is very dim or unreadable unless viewed in the dark.

Safety first: Only user‑accessible covers should be opened.

Steps:

• Replace batteries: Install new alkaline batteries to ensure full supply voltage.
• Check ambient temperature: If installed in a very cold area, move the thermostat to a more typical room location.
• Reset device: Perform a soft reset by removing power for a few minutes.
• Replace thermostat: If the display remains dim or segments are missing, the LCD/backlight assembly is defective; replace the thermostat.