Solve Your BMW HVAC Blower Failure in Santa Barbara
05 Nov, 19
BMW has remained at the forefront of pushing new technology development and increasing overall performance in their luxury vehicles. They still need to be regularly maintained to achieve optimal functioning, and this maintenance also includes caring for the HVAC systems.
The HVAC blower motor is responsible for running the fan in the BMW’s heating and air conditioning (A/C) system. Located inside of the dash, it can commonly be found on the inside of the engine compartment or on the steering wheel’s opposite side. The system’s blower motor plays an essential role in its general functioning, making it necessary to promptly address any issues with the HVAC blower. This article provides helpful information on how the HVAC blower works and how to diagnose problems and potential failure.
How the BMW’s HVAC Blower Motor Works
The blower motor in your BMW relays an electric current, which is connected to the vehicle’s control speeds. Any incorrect electrical current measurements can result in the resistor overheating and ceasing to function entirely. The fan may not operate at all if there is any malfunctioning in the HVAC system’s blower motor.
The blower motor’s speed is controlled by either a resistor or a motor control module. Blower motor resistors are simply electric resistors, which are used in cars where the HVAC only has a few fixed speed options. Alternatively, electronic motor control modules come equipped in vehicles with automatic climate control systems as well as automobiles with blower speeds that can be gradually adjusted.
If you find that the blower motor is not working at all, it is advised to first test the voltage of the turned-on blower motor connector. If the motor does not run but the testing shows that there are at least 4-6 volts on low speed and 12 volts on high speed, this is an indication of a bad motor. This needs to be replaced. It could also indicate that a blade has become jammed by debris. If testing reveals no voltage at the motor connector, the next step is to begin testing the entire blower motor circuit, starting at a fuse.
Common Culprits of a Bad HVAC Blower
Increased mileage and normal aging of a BMW automobile will eventually lead to common wear and tear of various inner components, and the HVAC blower motor is no exception. However, this general wearing can be reduced by frequently taking the car in for maintenance at a BMW-specific service shop.
Some of the more common causes and effects of a failed or failing blower include:
Electric Issues
Blower motors regularly fail due to various electrical problems. To perform a differential diagnosis on the HVAC system, gradually turn the power knob up to its highest air setting. If there is no airflow or an obvious reduction in airflow, there is likely not a problem with the HVAC blower motor itself but rather with an electrical issue.
Bad Blower Motor Resistor
Conducting a visual blower motor resistor inspection can be effective for revealing the main source of the issue. If you see no visual damage to the resistor, you should then check the resistance between the terminals to compare them to their specifications. After you replace a blower motor resistor, it is important to verify that the resistor was indeed the culprit by checking to see if the motor runs quietly and freely. If not, the motor itself is the source of the problem.
Low Refrigerant Levels
The temperature should significantly change when the A/C, heater, or defrost is turned on. If you notice no real difference, there may be a refrigerant (freon) leak. Since the purpose of refrigerant is to cool the air when turned to the A/C setting, any leaking freon will disrupt it from properly circulating throughout the system.
Our Five-Star Rated Service Center Can Help
Whether you are experiencing an HVAC blower failure or any other issues, you should feel confident that you are taking your beloved German vehicle 
to a high-quality service center. The incredible customer feedback that Santa Barbara Autowerks has received speaks volumes about the level of professionalism and expertise customers can expect.
Providing superior maintenance in both diagnostic and repair services to the Santa Barbara, CA area, our European automotive repair shop looks forward to becoming and remaining your primary dealership alternative. If you have any questions about your BMW, Audi, Volkswagen, Mini Cooper, Porsche, or Mercedes, please call us today to schedule a convenient appointment with one of our expert technicians.