What does it mean when a blower motor does not turn?

Changes in voltage indicate that the resistor is working and that the switch is able to vary the speed of the blower. If there is voltage but the motor doesn’t turn, disconnect the plug and connect one of the motor’s terminals to a good ground and the other to a 12-volt fused source. The motor should spin at its highest setting.

What are the symptoms of a failed blower motor resistor?

Blower motor resistor problems. Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at high speed and doesn’t work at low speeds.

What to do if your blower motor relay is failing?

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 from YourMechanic. They will be able to determine if the car will need a blower motor relay replacement, or a different repair, to bring full functionality back to your AC system.

Where does the power transistor go in a blower motor?

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. The service manual advises measuring the voltage at the blower motor, then if not OK, at the power transistor and so on.

Changes in voltage indicate that the resistor is working and that the switch is able to vary the speed of the blower. If there is voltage but the motor doesn’t turn, disconnect the plug and connect one of the motor’s terminals to a good ground and the other to a 12-volt fused source. The motor should spin at its highest setting.

Blower motor resistor problems. Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at high speed and doesn’t work at low speeds.

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 from YourMechanic. They will be able to determine if the car will need a blower motor relay replacement, or a different repair, to bring full functionality back to your AC system.

How is the speed of the blower motor controlled?

The blower resistor is connected in series to the blower fan motor. This means that the current running through the blower motor, and its’ speed is therefore controlled by the resistor value. The user chooses a fan speed by selecting a speed which then connects one of the resistors in the blower resistor pack.