Goodman Furnace Troubleshooting Flow Chart

Is your furnace... The problem might be your... What's wrong? How you can fix it:
Not heating? Circuit Breaker/Fuse Then either the circuit breaker has shorted, or the unit's fuse has blown completely. You'll have to reset the circuit breaker that connects to your furnace. If this doesn't help, then it's likely the fuse has blown, and you'll have to replace it.
Igniter The igniter is either defective or cracked. You should locate the igniter within your Goodman furnace and check the part for cracks. If it's cracked then replace the part, but it isn't then you'll have to test it with a multimeter for continuity to see if it's defective.
Cycling irregularly? Thermostat Your thermostat might be adjusting incorrectly. If your thermostat has an adjustable calibration scale, use this to adjust the heat anticipator. However, if this doesn't appear to work or you don't have a scale, you should replace the thermostat altogether.
Not blowing hot air? Blower Motor Your furnace's blower motor has either burnt itself out, or the connecting belt has snapped. You should check to see if power is reaching the motor. If it does but the motor isn't running, then the blower motor has failed. Alternatively, if the motor does run, but the air still doesn't move, then the connecting belt has snapped. Either replace the motor or belt depending on the situation.
Blowing too much air? Control Board The relay on your control board that regulates the voltage sent to the blower motor has failed. Should this occur, you'll have to replace the control board entirely.
Thermostat The contact on your thermostat that controls the blower motor is closed. You should use a multimeter to check for continuity. If the thermostat is functioning improperly, replace it altogether.
Starting and then stopping shortly after? Flame Sensor Your furnace uses a flame sensor to detect if a flame is present. If this sensor is defective or dirty, it will be unable to detect a flame. You should use a fine abrasive pad to clean the sensor if it's dirty. Otherwise, you can replace the flame sensor entirely.