One of the common luxuries most cars have these days is an air conditioner. This convenience helps keep you cool in the summer.
Another thing that most cars have today is a heating system to help keep you warm in the winter or cooler months. These to things do the opposite of each other, but they have one part in common.
That is the blower motor. In this article, we will look at what the blower motor is and also why it might stop working.
Sometimes it may stop working just at certain speeds, but in this article, we are going to mainly focus on why the blower motor won’t work on any speed.
Read on to learn everything you need to know about your car’s blower motor, why it might stop working, and also some solutions on how to fix it.
What Is Blower Motor?
Before getting into details of why your blower motor might stop working it is a good idea to have a basic understanding of what your blower motor actually is.
Your car’s blower motor is the part that is responsible for pushing air through your vents. This can be cool air from the AC or warm air from the heater, but it is your blower motor that moves the air thru the vents.
The blower motor is basically a high powered fan that pushes the air thru the system.
Blower motors can come in two types. A three or four-speed system, and a variable speed system. On a three or four speed system, this means that the motor will run at three or four predetermined speeds.
On a variable speed system it the blower will constantly change the speed that it is blowing. It is important to know what kind of blower you have because certain problems only happen with certain blowers.
Normally though variable speed blowers are on vehicles with automatic climate control where three or four-speed motors are on everything else.
Now that you know what the blower motor is we can start going into why it might not be working on any speed.
Reasons Blower Motor Not Working
There are a few reasons why your blower motor may stop working. We are going to list them out here and if you want to jump to a specific section you can, but the main reasons a blower motor will stop working on any speed is:
- A Bad Fuse
- A Bad Ground Connection
- A Bad Speed Control Module
- A Failed Motor
1/ A Bad Fuse
The most common reason why your blower motor won’t work on any speed is that you have a bad or blown a fuse. A fuse is a small wire inside of a connector that is used to protect the motor itself from a surge of electricity.
It is better for the fuse to blow if it gets too much of a current than for your whole blower motor to get fried. Most cars have the fuse in a fuse box under the hood or in a fuse panel under the dash.
You can locate the fuse to your blower motor. If it is blown, then all you have to do is replace it, and that should fix the motor.
You want to make sure to check the blower motor fuse and also the HVAC controller fuse because either one of these being blown can cause the blower motor to stop working. If it is not blown, then you will have to look farther into the issue.
Another thing that is tied to bad fuses is bad relays. The relays are basically larger fuses. Normally though they are not the issue if the blower motor won’t work on any speed though because there is a relay for high speed and low speed if it is something to keep in mind and check because it is possible that both could go bad at the same time.
This is especially true if they somehow got melted from getting too hot. It doesn’t take long to test relays, so while checking the fuses, you might as well check the high and low-speed relays to make sure they are working right.
2/ Bad Ground Connection
The next reason that your blower motor may not be working is that it might have a bad ground connection.
To test this, you can run a fused jumper from a battery to the power side of the motor and attach a temporary grounding jumper to the other motor terminal.
This will provide grounding for the motor, and it should run at high speed. If it does, then you know that the issue is that the motor is not being grounded. When testing your battery, if the battery has low charge, you can recharge it by using best battery maintainer, the tender will keep your battery fully charged and by the way, it will also minimize the risks of long-term damage to the battery due to either under-charging or over-charging
The way to fix this is to locate the grounding point for the motor and clean it. After a good cleaning and making sure the motor is connected to the grounding point try to power the motor using the car and see if it works. If it does, then your probably is solved.
Another way you can test to see if it is a bad ground connection is to disconnect the electrical connector at the blower motor and then attach a multimeter to the motor.
Then turn your key to the run position and see how much voltage you are getting. It should be 12+ volts. If you have a reading, then connect one lead to the power terminal on the motor and the other to the ground.
This will let you know if the ground is good. If it is, then you most likely have a dead motor, but if it isn’t, then that is a sign that the motor is not being grounded and you can clean it like previously mentioned.
This should fix the problem, but if it doesn’t, then you might have to try cleaning the grounding connection more, but first, you should check the speed control module.
3/ Bad Speed Control Module
The speed control module is responsible for controlling the speed of the motor. This is true for variable speed motors. If the speed control module goes out, then the motor will not run.
To test the control module, you can disconnect the electrical connector at the blower motor. Also, disconnect the jumper power and ground connections.
You want to bypass the speed control. Then run a fused jumper from a battery to the power side of the motor and connect a temporary grounding jumper to the other motor terminal.
The motor should run at full speed. If it doesn’t then the issue is something else. If it does run at full speed though, then you know that the issue lies in the blower motor speed controller or the HVAC control head, but you will have to use a scan tool to see which one of those is the problem and then have it replaced.
4/ Bad Motor
If none of these past things seem to be the problem, then the last bit is that you have a bad motor.
It is actually pretty uncommon for the motor to go out itself before something else and you normally have a warning when it is about to fail because it will start running poorly and squeak or slow down and things, but sometimes blower motors do go out.
If you can’t get the motor to run with these troubleshooting tips, then you will need to replace the motor because it is most likely dead, but do these other things first.
Knowing the circuitry of your motor is important because you will need to know that to find where the ground is and different things.
If you don’t know the circuitry of your motor or the type of motor you have, then you can look it up and find specific information for your vehicle. This is also important for locating fuses and relays.
Now you know the possible reasons why your blower motor won’t work on any speed. You know that the most common issue is a blown a fuse, but also sometimes the speed control module can go out if you have a variable speed motor.
You know how to check these things now though and also how to fix them. You also know that both variable speed motors and three or four-speed motors can suffer from bad grounding.
After reading this, you can test for that issue too and fix it.
Lastly, you know if all else fails, then the motor is probably bad and needs to be replaced. You know that the blower motor is the key part in moving the air in your AC and heat system and that you should replace a blower motor that isn’t working on any speed right away so you can stay cool in the summer and warm in the winter while driving.