Safety first: Turn off power to the furnace/air handler at the breaker before accessing the blower compartment.

Step 1 – Check thermostat fan settings: Ensure the fan mode is set appropriately (Auto vs On) and that any advanced fan circulation settings are configured correctly.
Step 2 – Inspect G wiring: At the thermostat and control board, verify the G wire is secure and not shorted to other terminals.
Step 3 – Test fan in manual mode: With power on, set the thermostat fan to On. If the blower does not run, suspect a control board or motor issue.
Step 4 – Inspect control board: Look for burnt traces or relays on the Carrier control board. Reseat blower motor harness connectors.
Step 5 – Motor diagnostics (advanced): ECM motors often have diagnostic LEDs or fault codes. Refer to the motor label and Carrier documentation to interpret any codes and determine if the motor is failed.
When to call a pro: Blower motor and control board replacement involve high voltage and should typically be handled by a technician.

Thermostat displays E16 and may not energize fan correctly; blower may not run or may run continuously.

Possible Causes