Safety: Turn off power to the furnace/air handler before touching wiring. Use a multimeter only if comfortable with low-voltage testing.

Step 1 – Verify system mode and setpoints: Ensure the ecobee is not in Off mode and that the heat/cool setpoints are set beyond the current room temperature.
Step 2 – Check equipment configuration: Go to Installation Settings > Equipment and confirm the correct system type (conventional vs. heat pump) and that stages are assigned to the correct terminals.
Step 3 – Inspect wiring: Confirm all control wires are secure at both the thermostat and furnace board.
Step 4 – Test outputs: With a call for heat or cool active, measure for 24 VAC between the active terminal (W or Y) and C at the furnace board. If ecobee is not energizing the terminal despite correct configuration, the thermostat may be defective.
Step 5 – Replace thermostat if outputs are dead: If wiring and equipment are good but ecobee never energizes outputs, replace the thermostat.

Thermostat is powered but does not turn on heating or cooling at all

Possible Causes