Blower Motor Speeds Up and Slows Down [3 Easy Solutions]

The blower motor speeds up and slows down because of three reasons. The first one is after many years of use, the blower fan wears off. That’s why the fan motor is not working. Then the inside atmosphere and the faulty actuators are also responsible for the blower motor speeds fluctuation.

However, whatever the reasons behind this blower motor issue, go on reading the article carefully. You’ll surely find the solution to a slow or speedy blower motor as you got from our torque increasing guide.

Car Blower Motor Speeds Up and Slows Down [3 Easy Fixes]

Here are the reasons and solutions to your car blower speed fluctuation issues:

1. Worn Out Motor

When you notice your car fan blower blowing a little amount of air, motor turning off and on frequently, then there is a possibility that it wears out for many years of use. Here the only solution is to replace the blower motor.

Sometimes, you will notice that the blower fan running at high speed with noise but cold air isn’t coming out of the vents. In such a case, there is a possibility that the blower motor fan is in good condition. Here the plastic blend door isn’t working. It might get stuck somehow. Then check the blend door and fix the stuck issue.

2. Inside Atmosphere

The blend door works completely depending on the atmosphere it’s in. When you ON the air conditioning mode, the blend doors block all the heat sources. And for this reason, no heat can be generated from the car engine. So, then only cool air comes inside the car.

But, for any reason, if the blend is a little bit open, then you will notice the blower is making a sound. Thus, you will find the fan speed may go out or slow down and a little amount of cold air coming inside the car.

In that case, the solution is to find out if there is any partial blend open or not. If yes, fix the gap.

2. Actuators

The actuators can be another reason behind the blower motor speeding up and down. You know the actuators control the car doors open and close. So, the actuator’s system fails for any reason, the door may get stuck or break down. And then your car ac fan would fluctuate.

Here you need to find out why the actuator system is not working and fix the trouble. Plus you should know, when an automatic temperature control system won’t work, you will find your blower isn’t working. And you are getting a small amount of cold air.

How To Take Care of Your Car’s Air Conditioners Fans

The best way to keep your air condition fan in good condition is to take care of it as well as the whole air conditioning system. As a result, the blower motor will function properly and provide you with cool air for a long time.

Very first you can maintain your blower by cleaning the cooling system regularly. It’s because dirt, dust, and obstacles take place in the blower system while functioning.

And remember, regular inspection and maintenance will surely increase the blower life span with better performance. 


Will a bad capacitor cause a blower motor to run slow? 

Yes, a bad bad capacitor will affect the fan performance and cause it slow runing.

What controls the blower motor speed?  

The blower motor resistor or the blower motor control module controls the blower motor speed.


Now you know why your car blower motor speeds up and slows down after reading the article. So, whenever, you face such a blower motor speeding issue, just check the above-discussed issues and fix the problem. And thus find your car ac blower is working fine.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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