The function of the car blower motor
The car blower motor is a core executive component in the car's air conditioning and heating systems. Its main function is to drive the fan to rotate and forcibly push air to flow, thereby achieving functions such as temperature regulation, defogging, and ventilation inside the vehicle.
Core Function
Supplying cold/hot air: The air from the air conditioning evaporator or the hot air from the heating box is sent into the vehicle through the air ducts, achieving cooling and heating functions.
Adjusting air volume and speed: By changing the input voltage of the motor through speed control resistors or electronic controllers, multiple speed settings can be achieved to meet different comfort requirements.
Removing fog and dehumidifying: In rainy seasons or when the car windows fog up, in conjunction with the air conditioning system, dry air is blown towards the windshield to quickly remove fog, enhancing driving safety.
Promoting air circulation: It supports both internal and external circulation modes, refreshing the air inside the vehicle, improving air quality, and reducing odors and pollutants.
Brief Description of Working Principle
After the blower motor is powered on, the coil generates a magnetic field to drive the rotor to rotate, creating an airflow. Modern vehicles mostly use speed control resistor control: By connecting resistors of different values in series to change the motor voltage, the speed can be adjusted. Some high-end models use electronic speed control modules, which have more precise response and lower energy consumption.
Fault Effects
If the motor experiences carbon brush wear, bearing jamming, or winding aging, it may cause:
Reduced or no airflow
Strange noises (such as buzzing or friction sounds)
Only the highest speed setting available (commonly seen in burned-out speed control resistors) Therefore, regularly checking the condition of the blower motor is of vital importance for ensuring the normal operation of the air conditioning system and the comfort of passengers and drivers.
The failure of the car blower motor is one of the common reasons for the malfunction of the air conditioning system. The symptoms and solutions are as follows:
Main symptoms
No air or very little air coming out of the air conditioner: The motor cannot drive the fan wheel to rotate, resulting in the inability to send cold or hot air into the cabin.
Abnormal noise: When the motor bearings are worn out or the coils are aging, they may emit "buzzing", "squeaking" or "clicking" sounds, especially more obvious at high air volume settings.
Overheated motor or burnt smell: Short circuits in the coils or long-term overload operation can cause abnormal motor temperature and even emit a plastic burning smell.
Blower cannot speed up or stops abruptly: In some models, the motor control module works in coordination with the motor body. Motor failure may cause the wind speed to be out of control.
Common causes
Internal motor failure: The armature coil burns out, shorts out or breaks, causing the motor to lose power output.
Worn bearings or lack of oil: After long-term use, lubrication fails, increasing friction resistance, causing the motor to run poorly, noise increases, and even get stuck.
Power supply abnormality: Poor contact of the power supply line, loose plug, or blown fuse, preventing the motor from obtaining sufficient current.
Control module or speed regulator failure: Some models control the motor speed through an electronic speed regulator. If this module is damaged, the motor may not start or operate abnormally. Solution
Initial Self-Check
Check if the air conditioning fuse has blown. If it has, replace it and check if there is a short circuit in the circuit.
Clean the air conditioning filter and the fan inlet. Eliminate the possibility of motor overload due to blockage.
Try switching to different fan speed settings to observe if all settings have no response or only certain settings are abnormal.
Professional Repair Suggestions
If the motor emits continuous abnormal noise or does not rotate at all, usually, the fan assembly needs to be replaced. Since the motor is often of an integrated design, replacing it separately is costly and difficult.
Use a multimeter to detect the motor's power supply voltage and resistance value to determine if it is a fault of the motor body.
If it is confirmed to be a motor bearing problem, some professional repair shops can provide disassembly and lubrication services. However, for safety reasons, it is recommended to replace the entire assembly with a new one to avoid secondary faults.
Replacement Suggestions
It is recommended to choose a regular repair channel to ensure compatibility of the parts and installation quality, to avoid line short circuits or air duct leakage caused by improper installation.
If you cannot determine or operate it yourself, it is recommended to go to a professional repair shop for diagnosis as soon as possible to avoid the expansion of the fault and affecting other components of the air conditioning system.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
