How does a blower fan resistor work?
How does a blower fan resistor work?
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The change in resistance then limits the current through the motor, which dictates the speed at which the blower fan operates.
Can a broken motor switch stop a blower?
A broken blower motor switch can also stop the blower from changing to certain speed settings. If your blower motor cannot change to certain speeds, check both the resistor and the switch on your dashboard. The most common failure points are the resistor and the motor itself.
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.
How does a blower motor resistor control the fan speed?
The blower motor resistor controls the fan speed of the blower motor and the resulting change in air pressure produced by the movement of the blower fan. It accomplishes this by regulating the electric current that powers the motor.
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.
Why is the resistor not working on my blower?
Hi There, The resistor is what controls the speed of the blower motor, not the relay. The blower motor relay supplies power to this motor when you turn the switch to “on” that can sometimes fail. When this happens, you may notice that you will not feel anything blowing out of the vents at all.
What happens when the blower motor switch stops working?
When this happens, one or several of the blower fan speeds stop working. The cool thing is that diagnosing/troubleshooting the blower switch isn’t hard. The following circuit descriptions will help:
Where is the blower motor resistor located on a car?
It’s located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
Do you have to replace the blower switch?
You don’t have to buy the whole A/C-Heater Control Panel to replace the blower control switch since the switch is removable. If you’re interested in the original Ford Motorcraft blower switch or on an after-market part (and save), the following links will help you comparison shop.
