Strange Rattling, Clanking, or Screeching One of the first signs you may notice when there's an issue with the blower motor is a strange noise coming from the indoor unit or air handler.
A failing blower motor may emit unusual sounds. This may sound like screeching or squealing if it has bad bearings. You may hear a rattle or a banging sound if something inside the motor has broken or come loose.
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.
WEAK AIRFLOW OF THE BLOWER MOTOR
The fans will work at certain speeds until they stop working altogether. Such a fault not only results in poor airflow but also decreases the efficiency of the defroster as it uses the same fan to blow air at the windshield.
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.
The blower motor resistor controls the speed of the fan and is critical in regulating the temperature and airflow inside the vehicle. If the resistor fails, the air conditioning and heating system may not work properly, which can affect passenger comfort.
A bad blower motor can cause the HVAC system to use more energy and drive up your heating bills, and is one possibility that should be investigated if you notice a spike in your winter utility expenses.
To test the fuse, set your multimeter to the continuity test setting. Then, touch the probes to either side of the fuse. If the fuse is OK, the multimeter should beep or indicate that you've completed the circuit. If you get no such indication, that means the fuse is bad and must be replaced.
The engine will stop running, and your vehicle won't move or start. Main relay problems could also lead to your engine running for a while or a very short time. Your vehicle might start normally sometimes but not start at all at other times.
A defective ground wire or ground wire connection and an open circuit in the power-side circuit (including the fuse, wiring, and fan switch) are the most common reasons why a blower motor fails.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.
Intermittent Operation
When this happens, there's usually something wrong with either the blower motor itself or with another part of your furnace that controls it. Problems include dirty filters, broken wires, poor voltage supply and faulty limit switch or capacitor.
If your blower motor is experiencing some issues, you may hear a high-pitched squeal or whistling sound. You may also experience rattling and loud screeching noises. The motor blower pushes warm air out of the furnace through the ducts into your home.
Blower motor is fuse 35 and is a 40 amp. You could test them with a meter or visually look to see if they're blown, then take it to a shop if they blow after replacing them.
Weak or Absent Airflow
Weak airflow or total lack of it is the most obvious sign of a bad blower motor. The problem could be due to a clogged blower from accumulated dust or debris. It could also be due to leaky air ducts or a bad capacitor.
Replacing the blower motor is likely the best decision if your furnace is under warranty or relatively new. It might be better to replace the furnace if it's old or has a lot of issues that require frequent repairs. On average, a new blower motor costs $300 to $900.
Weak or no airflow
If you put your hand up to your air vents where air normally blows out and you discover no flow or weak airflow, the cause could be a blower motor failure.
Car AC Not Blowing Cold Air: A Bad Fuse
Find the fuse associated with the A/C blower motor. If the blower motor fuse is still in-tact, your problem is located elsewhere. If the fuse is blown, simply replacing the fuse with an identical fuse of the same amperage rating could get your system working again!
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.
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.
The AC system is responsible for circulating air through the system and into your home. Therefore, if you notice that there is low or no airflow from your vents, it's an indication there may be a problem with your blower motor that needs repair or replacement by a professional.
The average cost for a Blower Motor Resistor Replacement is between $119 and $154. Labor costs are estimated between $43 and $54 while parts are priced between $76 and $99.