What are the symptoms of a worn out blower motor?

One of the symptoms of a worn out blower motor is that it can intermittently produce a loud screeching noise when running. How to test a blower motor? If the blower motor doesn’t work at all, the blower motor itself must be tested first. Typically it’s done by measuring the voltage at the blower motor connector when it’s turned on.

How is the speed of the blower motor controlled?

The electronic module that controls the speed of the blower motor is called a blower motor control module. In some cars, the blower motor has only 4 or 5 fixed speeds. In this case, the speed of the blower motor is controlled by a blower motor resistor.

What does it mean when a blower motor resistor fails?

In our case the ohmmeter shows open circuit, which means the resistor has failed. Sometimes, a blower motor resistor might fail due to problems with the blower motor itself. This means after replacing the blower motor resistor, check if the blower motor runs freely and doesn’t make any noise.

Where is the blower motor under the hood?

If you cannot find the blower motor under the hood it will be located under the dash on the passenger side. You may need to remove the mounting screws of the lower panel to gain access to the motor for removal. This heater motor location is under the dash. Let’s start the removal which is the same for under hood or dash applications.

Where does the ground go in a Honda blower motor?

The blower motor control module (Honda calls it Power Transistor) supplies the ground. The power transistor has 4 wires: two come from the climate control system control unit, one is the ground, one goes to the negative terminal of the blower motor.

What are the symptoms of a bad blower motor relay?

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.

Where is the blower control switch on the dashboard?

The blower control switch on the dashboard controls the circuit flow of the blower motor to adjust the voltage from low, to medium, to medium-high, to high. When on high, the circuit bypasses the blower resistor.

What causes a Nissan blower motor to run slower?

The auto AC regulates the fan control amp, which regulates the voltage to the blower motor. A low speed setting causes a lower voltage across the blower motor, which makes the motor operate slower. At maximum fan speed setting, the fan control amp allows nearly all 12v across the motor, which causes the fan to run faster.