Amazon Smart Thermostat display lights: what each one means

Where does Amazon explain each light and icon?

In the Alexa app, not on its website. Amazon's help page with this title points you to an icon guide inside the app: open Devices, choose Thermostat, select your Smart Thermostat, then Device Settings, Thermostat configuration and Thermostat icons. Tap any icon there to read what it does.

That guide is the reference for your exact thermostat and software version, so use it when an icon on the wall does not match anything below. The help pages on amazon.com describe only a handful of the display states, and we list just those here.

What does the colored Info icon mean?

An alert. Amazon says the Info icon on the left side of the display means you have an alert or notification about the thermostat. When it shows in red, yellow or green, Amazon's instruction is to open the Smart Thermostat page in the Alexa app, where the message itself appears.

Amazon does not publish what each color stands for, so we do not guess. Read the alert in the app; it tells you more than the color can.

What do the other display states mean?

Amazon Smart Thermostat display states that Amazon describes

On the display	What Amazon says	Amazon help page
Info icon in red, yellow or green, on the left	You have an alert or notification about the thermostat	Display lights
Flame icon lit	Heat mode is selected; you press the Mode button until the flame lights	Heat troubleshooting
Mode indicator	Press it to switch between cooling, heating and fan modes	Adjust temperature manually
Dim display	The display can dim when inactive; touch it to see the full display	Display is blank
"rEs"	Shown after holding the reset buttons for 10 seconds	Partial and full reset
"sET"	Shown after the five-second countdown of a full factory reset	Full factory reset
Red exclamation mark	After a partial reset, the thermostat is ready to be set up again	Partial reset

Why did my thermostat show "rEs" or a red exclamation mark?

Someone started a reset. On the Amazon Smart Thermostat, a partial reset begins by holding the Up Temperature and Mode buttons together for 10 seconds; a full factory reset uses Up, Down and Mode together. Either way "rEs" appears. Holding Mode through a five-second countdown then completes it.

After a partial reset, Amazon says to wait for a red exclamation mark, which means the thermostat is ready to be set up again in the Alexa app. A partial reset keeps the HVAC configuration but erases everything else, so check your schedule periods and Alexa Hunches once it is back online. After a full reset Amazon says "sET" appears, and you remove the thermostat from the Alexa app and set it up from the start. When and why to use each reset is covered on Amazon Smart Thermostat not responding.

Why is the display dim or dark?

Usually because it is idle. Amazon says the display may dim when inactive; touch it to bring back the full display. The Alexa app has separate brightness levels for the active and inactive display: open the thermostat, then Settings, Thermostat configuration, Display brightness.

If touching it does nothing and brightness is already up, the screen is blank rather than dim. Amazon attributes a blank screen to wiring and power, which is work for a licensed HVAC technician, not something to change from the thermostat. Our blank thermostat screen page covers that case across brands.

What if the Alexa app shows a configuration failure?

Amazon says the thermostat may send a configuration failure notification to the Alexa app during setup, and that in most cases a restart fixes it so the thermostat can install updates. To restart, remove the faceplate from the wall plate, wait a few seconds, then gently reattach it. If a second configuration failure arrives, Amazon says to contact its customer support.

Is it the Info icon on the left, in red, yellow or green?

• Yes

  Open the Smart Thermostat page in the Alexa app and read the alert there.

• No

  Is the screen dim, or does it show "rEs", "sET" or a red exclamation mark?

  • Yes

    Touch the display to wake it, or finish setup in the Alexa app if a reset was started. See the table above.

  • No

    Look it up in the Alexa app: Device Settings, Thermostat configuration, Thermostat icons.

Two settings that change how the thermostat runs are not on the wall at all. On a heat pump, emergency heat (EM heat) is switched on in the Alexa app under Device Settings, Thermostat Configuration; how it differs from auxiliary heat (AUX) is explained in auxiliary heat vs emergency heat. Vacation Mode is also in Device Settings, where you set the heat and cool temperatures Alexa keeps while you are away; see vacation hold. More Amazon pages are on the Amazon Smart Thermostat hub.