Indoor blower runs continuously even when thermostat is not calling for heat or fan.

Steps:

• Check thermostat fan setting: Ensure the fan is set to AUTO, not ON.
• Observe LED codes: If a limit fault code is present, the board may be running the blower for safety; troubleshoot the limit issue first.
• Test G circuit: Disconnect the G wire at the control board. If the blower stops, the thermostat or wiring is holding G energized.
• Check control board: If blower runs with G disconnected and no fault codes, the blower relay on the board may be stuck and the board will need replacement.

Always turn off power before disconnecting or reconnecting thermostat wires.