Generic · Furnace / HVAC
Blower runs constantly Blower motor / fan relay stuck on
What this code means
The indoor blower keeps running even with the thermostat satisfied, usually a relay or fan-limit setting issue rather than a numbered fault.
Most likely causes
- Fan set to "on" instead of "auto" at the thermostat
- Stuck fan relay on the control board
- Fan limit switch miscalibrated
What to try first
Check the thermostat fan setting is on "auto," not "on."
Good news: this one is often fixable without a service call. If it persists after the steps above, have it looked at.
FAQ
What does Generic error code Blower runs constantly mean?
Blower motor / fan relay stuck on. The indoor blower keeps running even with the thermostat satisfied, usually a relay or fan-limit setting issue rather than a numbered fault.
Can I fix Generic code Blower runs constantly myself?
Often, yes. Check the thermostat fan setting is on "auto," not "on."
What causes Generic code Blower runs constantly?
The most common causes are: fan set to "on" instead of "auto" at the thermostat; stuck fan relay on the control board; fan limit switch miscalibrated.
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This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.