The part(s) or condition(s) listed below for the symptom Air handler blower not running/not turning on are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The run capacitor provides an electrical charge to start and run the blower motor. If the capacitor is defective, the blower motor might be noisy, overheat, or not run at all. To determine if the run capacitor has failed, you can inspect the capacitor for signs of visible damage. If the capacitor is bulging or leaking, replace it. The capacitor can also be checked with a meter to determine if it is capable of storing and releasing a suitable charge.
The capacitor provides an electrical charge to start and run the blower motor. If the capacitor is defective, the blower motor might be noisy, overheat, or not run at all. To determine if the capacitor has failed, you can inspect the capacitor for signs of visible damage. If the capacitor is bulging or leaking, replace it. The capacitor can also be checked with a meter to determine if it is capable of storing and releasing a suitable charge.
The control board regulates the power supply to all of the components of the furnace or air handler. If the control board is defective, it might not send voltage to the blower motor.
Check the blower wheel to ensure that it spins freely. If the wheel is obstructed, that will prevent the blower from running. A damaged blower wheel and housing should be replaced. If the blower wheel and housing are in good condition and unobstructed, but the blower wheel does not spin freely, the the blower motor has likely seized and will need to be replaced.
The furnace or air handler blower motor is the component that circulates the air throughout the home. If power is getting to the blower motor, but the motor does not run, the motor may be burned out. If the blower motor is burned out, replace it. If the blower motor hums, check the blower fan to ensure that it spins freely. If the blower fan is unobstructed but does not spin freely, replace the blower motor.
Check to ensure that power is getting to the air handler. If the air handler is not getting power, check the circuit breaker or fuse.
Check to see if the furnace or air handler blower comes on when you jump the control board contacts for the red (“R”) and green (“G”) wire terminals. If it does, then it's likely the wall thermostat is defective and unable to alert the furnace or air handler control board to turn on the blower. You will need to replace the wall thermostat to regain control of the blower.
Check to see if the furnace or air handler blower comes on when you jump the control board contacts for the red (“R”) and green (“G”) wire terminals. If it does, then it's likely the WiFi thermostat is defective and unable to alert the furnace or air handler control board to turn on the blower. You will need to replace the WiFi thermostat to regain control of the blower.
