Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Blower Motor Relay

Blower motor relay

The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. The blower motor is the component responsible for pushing air through the vents of your vehicle’s heating and air conditioning systems. Without it, the AC system will not be able to circulate the heated or cooled air. The blower motor relay controls the current used to power the blower motor, and is subject to the constant on and off switching. Over time, it will eventually wear out. When the blower motor relay does begin to fail, the vehicle will usually display a few symptoms that can alert the driver of a potential problem that should be serviced.

1. Blower motor does not function

One of the first symptoms of a problem with the blower motor relay is a blower motor that does not function. As the relay is the switch that supplies current to the blower motor, if it fails internally, then power may be cut off from the blower motor circuit causing the motor to no longer function.

2. Blown fuses

One of the first symptoms of a bad or failing AC blower motor relay is a blown AC blower motor relay circuit fuse. If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.

3. Melted relay

Another, more serious symptom of a problem with the blower motor relay is a burned or melted relay. Relays are exposed to high current loads and can sometimes get hot when they develop problems. In serious cases, the relays may heat up to the point where the interior components and plastic housing of the relay will begin to melt and burn - sometimes even causing damage to the fuse box or panel as well.

Since the blower motor relay is essentially the switch that directly controls power to the blower motor, the entire AC system will be left unable to distribute its cooled or heated air if the relay fails. For this reason, if you suspect that your blower motor relay is having a problem, have the vehicle’s AC system diagnosed by a professional technician, such as one from YourMechanic. They will be able to determine if the car will need a blower motor relay replacement, or another repair, to bring full functionality back to your AC system.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Vacuum Brake Booster Check Valve Last?
The braking system on your car requires a lot of pressure. The vacuum booster is one of the main sources of this pressure. This booster will take the pressure that...
How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...

Related questions

Q: I have Chrysler 300c. Battery light came on, changed battery and alternator but power still getting drained and battery light still comes on.

Hi, thanks for writing in. This may be a sign of a failing starter relay. The starter relay is a small unit near the starter that directs power to the starter from the battery. When this fails, it may cause...

Q: What Causes a Car's AC System to Rattle When It Is Turned On?

The cause of the rattle will depend on whether it is coming from inside the car or under the hood. Typically, a rattle would be associated with the compressor and underhood components. Let’s take a look by starting under...

Q: A.c. running when engine is off.

The blower resistor is shorted and causing the blower to stay on. The resistor is in the blower housing. You will want to have the resistor replaced with a new one in order to remedy this problem.