E14
Amazon Smart Thermostat
Display Power / Backlight Fault
Thermostat shows E14 and screen is very dim or flickers
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Low 24V supply voltage, Loose R or C connection at thermostat, Failing backlight driver on main PCB
How to Fix / Troubleshooting
Safety: Turn off power to the HVAC system at the breaker before checking wiring.
- Check R and C connections: Remove the thermostat and verify that R and C wires are fully seated in their terminals and not loose.
- Measure voltage (if you have a multimeter): With power on and thermostat removed, measure between R and C at the wall plate. It should be around 24 VAC. If significantly lower, the furnace transformer or wiring may be faulty.
- Reseat thermostat: Firmly snap the thermostat back onto the wall plate to ensure good contact.
If supply voltage is normal and E14 persists with a dim/flickering screen, the display/backlight circuit is likely failing. Replace the thermostat.
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Repair Difficulty
Medium
3/5
Required Part
Amazon Smart Thermostat Main Control Assembly
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