Drivers of BMW’s expect a comfortable and reliable experience coming from their luxury vehicle. This is a car that you can expect high performance and all the creature comforts rolled into one beautiful vehicle. As with all cars, parts wear out and break. Regular maintenance, service, and repairs are just part of the car ownership experience, and your HVAC system is no different.
The blower final stage fan resistor sounds really impressive or complicated, but it is simply an electrical component under the hood of your BMW. It provides voltage to the HVAC fan and blower. When this piece does not work or fails, you will not have the ability to heat or cool your car. You will also not be able to use your window defrosters.
Causes of the Final Stage of Blower Fan Failure
In most cases, the blower fan resistor is failing either due to overheating or corrosion. If the blower fan fails, your car will not blow any forced air. However, sometimes the problem can be with the blower motor itself. This is especially apparent when you have replaced the blower fan multiple times.
Although it is possible to get a bad part or two, it is rare. If you have to replace this more than once on your BMW, you should ask your mechanic to do a thorough check of the blower motor. It is possible that replacing this part will solve all your problems with heating and cooling inside your BMW.
Six Symptoms of Blower Final Stage Fan Failing
There are many different symptoms of a potential problem with your blower resistor. Check out the 6 possible signs below to see if there are any that you notice from your own experience with your car.
- The fan will not turn off: If you try to turn your fan off, and no matter what you do, it will not turn off, there is a problem with your final stage fan. The blower resistor is not regulating the electrical current correctly, and this is why the fan will not turn off.
- The fan will not turn on/No air comes out: If you try to turn the fan on and nothing happens, you also have a problem. Besides it not coming on at all, you might also notice a problem with airflow. For instance, the airflow seems lower than it once was, regardless of what speed you turn it up to. This indicates that the electrical current is not being adequately regulated. It may be due to your blower fan resistor.
- Low speeds only: Your fan is only working at low speeds. Whenever you turn the fan up to a higher rate, the fan stops. Depending on whether it is a wiring issue or just an overall failure, this can happen. You will need your mechanic to properly diagnose the problem, though, because this is also a common symptom of your HVAC blower failing.
- High speeds only: Sometimes it may seem fine if you always use the heating, cooling, and defrosting fans on high because it functions on demand. However, if you try to turn it to lower speeds, it may stop working. This seems confusing because if it can operate at high speeds, why would it not work at low speeds? This is a symptom that the HVAC blower is fine, but the problem is squarely in the resistor. When the fan is at high speeds, there is nothing that needs to be modulated. So, if it works at high speed only, the problem is the fan resistor.
- Bad Smells: You could smell a foul smell. It may even smell like something is burning. This occurs because either plastic or metal components are overheating.
- Smoking Vent: If smoke is coming out of the vents, this could be the blower resistor, but it is more likely an issue with the HVAC blower. If smoke or foul smells are emitting from your vents, you should immediately pull over to a safe spot and contact our mechanics for service and repair.
Call The Pros at Ultimate Bimmer Service Today
The service technicians and mechanics at Ultimate Bimmer Service take care of BMW customers in Carrolton and Dallas, TX. If your vehicle is exhibiting any of the symptoms mentioned on this page, call us to make an appointment to bring in your BMW right away.
We have formally-educated, factory-trained BMW Master Certified Technicians with a combined 30-years of experience repairing and servicing BMWs. We are ASE certified, have factory diagnostic equipment, and use original BMW parts and accessories. Call or stop by today!