What should I do if my furnace blower is not working?

What this symptom usually points to

When the furnace blower is not working, the specific problem is air movement inside the furnace, not just heat production. The burners or electric heat strips can come on, but if the blower does not push that heat through the ductwork, rooms stay cold, airflow at the registers is weak or absent, and the furnace often shuts itself off to avoid overheating.

What you can notice from the way it fails

A blower problem that begins suddenly often points to an electrical part such as the run capacitor, fan relay, control board, or a wiring interruption. A blower problem that worsens gradually is more consistent with a motor wearing out: airflow may have been getting weaker for days or weeks, the furnace may have run longer than usual, and you may have heard the fan start slowly, squeal, or hum before it stopped altogether.

If the whole home is affected, the issue is usually at the furnace itself because one blower serves the system. If only one room or zone seems affected, the blower may actually be running and the problem may be downstream, such as a closed damper, disconnected branch duct, or zone-control issue; however, a variable-speed blower that is failing can also make some rooms lose airflow before others do.

Clues that help separate the likely causes

A humming furnace with no airflow often matches a bad capacitor or a motor that is trying and failing to start. Burners that light and then shut off after a short time suggest the furnace is overheating because the blower never came up to speed. A furnace that seems completely lifeless except for the thermostat display can point more toward a tripped breaker, door switch issue, or control failure than toward the motor alone.

What a technician typically does on the visit

A service visit for this symptom usually starts with confirming whether the thermostat is calling for fan and heat, then checking blower power, control-board output, safety switches, capacitor readings, motor amp draw, and whether the blower wheel turns freely. If the furnace heats but the fan does not start on command, the technician narrows the problem to the blower circuit rather than the ignition system. Common repairs include replacing a capacitor, motor, relay, board, or repairing damaged wiring and then verifying normal temperature rise and airflow.

What affects repair cost

Cost depends mostly on which blower component failed and whether the furnace uses a standard PSC motor or a variable-speed ECM motor. Typical 2025-2026 US repair ranges are about $170-$575 for a capacitor replacement, $500-$1,575 for a standard blower motor job, $1,300-$3,900+ for an ECM motor/module, and roughly $500-$1,575 for many control board replacements. Labor can increase if the blower assembly is hard to access, the system is older and parts are scarce, or overheating has damaged more than one component.