Detecting a Failing Blower Motor Resistor in BMW Models

Riding a BMW is pleasurable until its blower motor resistor malfunctions and the A/C or heater starts acting up, disrupting the optimal airflow. Well, when it fails, it can not only frustrate you in extremely hot or cold weather but also ruin the overall comfort and quality of the ride and cause permanent damage to the A/C or heater if left untreated. Don’t panic! Stick to the end of this comprehensive guide to discover the typical warning signs of a faulty blower motor resistor so that you can easily recognize the issue and fix it with effective repair strategies to avail flawless driving experience in your cherished BMW.

What is your BMW blower motor resistor, anyway?

Before delving into the common indicators of the malfunctioning blower motor resistor, let’s figure out its key responsibilities. Your BMW blower motor resistor is something in between the climate control system and the fan. Usually, its primary task is to regulate the fan speed according to your chosen airflow speed, like low, medium, or high, ensuring the fan operates at the selected speed. Thus, if it fails, it can completely knock out the airflow system, delivering poor airflow instead of offering a refreshing one.

Evidence of your BMW’s damaged blower motor resistor

 The fan is stuck at one speed: You may encounter the fan functioning at a single speed either high or low with a failed blower motor resistor. Because a malfunctioning resistor can’t manage voltage levels for different fan settings.

 Fan works inconsistently: One of the most common symptoms of a defective blower motor resistor is sometimes the fan runs and the rest of the time it doesn’t work at all.

 No airflow from the vents: In worst the case, the heater or A/C stops blowing any air out of their vents. This happens when the blower motor resistor is completely out of order.

 Burning odor or excessive heat: At the starting stages of the blower motor resistor failure, it starts producing excessive heat and as a result, you may smell a burning plastic odor.

 The fan doesn’t blow at the selected speed: When the blower motor resistor gets damaged it can completely mess up the airflow. For instance, if you select the fan to blow air on a low setting, it may blow too much air or if you choose the medium setting, it may blow negligible air out of the vents.

Why does your BMW’s blower motor resistor stop working?

 Like any other electrical component, the blower motor resistor also ruptures due to aging. Moreover, if you use the A/C or heater more frequently, it can slowly hamper its efficiency, causing premature wear.

 Various natural factors like water droplets or dampness can enter into the blower motor resistor and cause corrosion or short-circuit.

 Sometimes, electrical troubles like loose connections or worn wiring can be the reasons behind a poor blower motor resistor.

 If the blower motor is defective or blocked with dirt or debris, it consumes excessive power, ultimately overheating or putting additional stress on the resistor.

How to troubleshoot the problem?

 First, turn on the climate control system and try to hear the fan’s noise. If the fan doesn’t function or behaves abnormally, the defect might be in the blower motor resistor.

 Next, try to modify the fan settings. If the fan speed doesn't change or gives a delayed response, the resistor might be on its last leg.

 You can refer to the manufacturer’s manual to find the resistor, which is usually behind the glove box or near the blower motor. If you have basic repairing skills, you can check the resistor for any signs of corrosion, burning, melting, or cracking.

 Using a multimeter, you can test the electrical resistance of the resistor. If you observe discontinued readings, it’s time to replace the faulty blower motor resistor.

Final thoughts

Alright! Now you know the warning signs of a malfunctioning blower motor resistor, its causes, and the effective tricks to diagnose it. So, whenever you face the above issues, you must visit the nearest BMW workshop and seek professional assistance to repair or replace the poor resistor, as ignoring it can wear out the nearby auto parts, draining your wallet on unnecessary repairs down the road. So, don’t let this little issue ruin your ride, and replace the faulty resistor with a new one to ensure a seamless ride with your loved ones.