When does a blower resistor need to be replaced?
If power is present on the fan’s terminals and the fan is not working, the blower fan is defective. If the fan operates at some speed settings, but doesn’t work at some other speed settings, this means that the blower resistor is faulty and should be replaced:
What happens when a cooling fan resistor fails?
The cooling fan resistor is meant to send power to the fans in steps, so that the fans may operate at different speeds. If any of the individual steps or switches fail, it will disable the cooling fans from operating on that speed setting. You may notice that the cooling fans only operate at one speed, when they used to operate on two or more. 3.
How does resistance affect the speed of a blower fan?
The lower the resistance of the selected resistor in a pack, the higher the current that flows through the blower fan, and the faster the fan will turn.
How can I change the speed of my blower fan?
The fan speed can be changed either by switching the blower resistor resistance mechanically, using a rotating lever, or electronically by the air conditioning system. The change in resistance then limits the current through the motor, which dictates the speed at which the blower fan works.
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.
What is the resistance of a fan resistor?
Again, ohms law suggests that at full speed this fan has a resistance of 5.2Ω so adding an 11Ω resistor in series should drop the overall current to 0.74A (8.9W rather than 28W) with 6W through / 8.1V across the resistor and 2.9W through / 3.852V across the fan.
What happens when a heater motor resistor fails?
If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. The heating and air conditioning systems may still function at one speed, however the resistor will have to be replaced in order for full functionality to be restored. 2. Blower motor does not work on certain settings
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.