No Airflow
If you notice that there is no warm air at all coming through your heat registers, then you may have a broken blower motor. This generally means the blower motor has failed completely, which may indicate there have been problems for a while.
Blower motors are designed to last just as long as your furnace itself, anywhere from 10 to 20 years. Just as with any HVAC system, the better maintained and serviced your equipment is by experienced HVAC technicians the longer it will last and the fewer repairs you'll face.
The replacement of the blower motor is common and straightforward, so most shops will perform the repair — many on the same day.
It typically takes one to four hours for the technician to replace the AC fan motor. Normally, good technicians will check for other issues during this replacement. If more problems are found, they will be repaired as well.
A Failed Motor
An HVAC blower motor will occasionally fail due to age, wearing out, or not being cleaned regularly. Symptoms may include strange noises, burning smells, or just plain refusing to turn on. If this happens and the motor is no longer operable, a new blower motor may be needed.
If the blower motor is going bad, it will struggle to operate the fan. The result will be weak airflow coming from the vents inside your living spaces. This airflow issue can be one of the main symptoms that indicate the component needs to be replaced.
Blower Motor Resistor Test
Typically, if the fan will work on some speeds but not on others, the resistor is suspect. Okay, let's say there's no melting going on, but your fan doesn't work on all speeds. Typically, if the fan will work on some speeds but not on others, the resistor is suspect.
On some platforms, a faulty blower motor relay will cause the blower not to work at all, which means there will be no airflow from the A/C. On others, the blower won't work on “high blow” but all the other speeds will work. The blower motor relay fails because it regularly deals with high current loads.
Although AC fan motors can last 10-15 years or more, a lack of regular maintenance can shorten their lifespan. Here are some signs you may need AC fan motor replacement.
If the motor is making rattling, clanking, or banging sounds, it may be because of a loose or broken part inside the system. Loud banging sounds are especially worrisome. They're usually a sign that something within the system is damaged or disconnected, potentially indicating the need to replace the blower motor.
If your motor's electrics and bearings are constantly exposed to too much heat, then they will begin to fail. If you let your motor overheat repeatedly and fail, then either a component has broken or a bearing has seized.To prevent overheating, check your vents, filters, and in-room airflow.
Average Costs for Blower Motor Replacement
Standard Blower Motors: These might cost between $400-700, excluding labor. Advanced Multi-Speed or Variable-Speed Motors: These are generally more expensive, with costs ranging between $650-1250, not including labor.
Typically, the lifespan of furnace blower motors spans from a minimum of 10 years up to about 20 years, with most enduring an average period between 15 and 20 years.
The Cost of Not Replacing It
Because of how hot the system runs, running your AC with a failed fan motor could result in your compressor failing, too. The compressor is a much more expensive component, typically running $1,400-$3,000, so procrastinating on AC repair could be a very costly delay.
However, they can eventually burn out, so if your AC unit's blower motor is old, it might be time for a new one. One sign of a faulty blower motor is an air conditioner that still runs without blowing cool air. Remember: If the blower motor stops working, air is not moving through the system.
In general, a blower motor should last for the lifetime of your vehicle if it is properly maintained. However, it is not uncommon for blower motors to fail prematurely due to factors such as wear and tear, corrosion, or electrical issues.
There are several ways you can tell if your blower motor is going bad. One way to tell is by listening for strange noises coming from the motor. Another way to tell is by checking the voltage at the motor terminals. If you notice that the voltage is low, this could be an indication that the motor is going bad.
The most common reason why your blower motor won't work on any speed is that you have a bad or blown a fuse.
An air compressor operates at a high pressure to volume ratio, while an air blower tends to operate at a low-pressure ratio. A compressor crams air into a small space which makes the air denser. A blower moves air/gas with a moderate increase of pressure.