The blower motor is an important component to a working heating and air conditioning system in your car. It is the main electric motor that helps blow the air through the vents. If the blower motor is going bad or there is something caught in the fan, then heat or air conditioning won’t blow properly through the vents and you’ll be left with an uncomfortable driving experience in extreme heat or cold.
Before you start troubleshooting your blower motor, double check to make sure that what you think might be problems are actually just normal processes of the car heating and air conditioning system. In older vehicles, the fans only start working when the vehicle reaches a certain temperature. This process is meant to prevent the car from pushing cold air through the vents when you’re wanting to heat it up.
If your car has that climate control feature, then everything is working fine. If it doesn’t, then there might be a problem that you’ll need to fix. Troubleshooting your blower motor isn’t too difficult, if you know what you’re looking for. This guide can help you find and fix any problems you may be experiencing with a failing motor blower.
Signs Your Blower Motor is Going Bad
Your Fans Only Blow at Certain Speeds
If you turn on the air, and the air only blows at certain speeds, then you may have an issue with your blower motor. You can normally diagnose this problem by paying attention to what control speeds the fan is blowing at. Since blower motors have a simple design - the motor itself, the switch to run it, and a resistor or transistor that controls the blower speed. So if the motor only blows at a certain speed, then it’s likely the transistor or resistor assembly that’s going bad.
When Your Air Blows, It’s Weak
Your blower motor may be going bad if you turn on your air conditioning and the air blowing out of the vents is weak, even on the highest vent setting. If that is happening, then that is generally an indicator that the blower motor is starting to fail. It may be that you can replace certain parts to the motor to get it up and running, but you may have to replace the entire assembly. An easy test of the blower motor system will help you determine that.
No Air at All From the Vents
If you turn on your climate control in your car and there is no air flow from the vents, then it’s a sure sign that your blower motor has short-circuited or burnt out. If you notice this in your car, then you’re likely going to have to replace the blower motor or the fuse to get the air conditioning back up and running.
Smoke or Burning Smell in the Cabin
An extreme sign that the blower motor has failed is if you notice smoke or a distinct burning smell coming through the vents. If this happens while you are driving, pull over immediately and turn off the car. You should double check to make sure that the problem isn’t due to something else by getting under the hood and having a look. If the circuit has burnt out in the blower motor, then you’ll be able to tell by checking where the smoke is coming from.
How to Test Your Blower Motor
Check for a Blown Fuse
Turn off your car and pull out your vehicle manual to find the location of the fuse box. It should help you locate the fuse box. Most fuse boxes are located in an easy-to-reach place under the dashboard or in the engine bay. Once you’ve found the fuse box, check to see if the filament in the fuse has burnt out. If it has, replace the fuse.
Turn the car back on and make sure the fuse holds. If your air conditioning starts working normally again, then you know it was just the fuse. If it blows again, check to see if there’s a loose circuit.
Check for a Loose or Failing Circuit
To check the wiring, first locate the blower motor. You can usually find it under the dashboard on the passenger side of most vehicles, but double check in your owner’s manual for the exact location. Older model vehicles placed the blower motor on the passenger side firewall, which can be accessed by going under the hood.
Once you find it, check to see if any plugs have been kicked loose. If they have, re-connect the plugs and try the climate control again. If it doesn’t work, then you may have to check the wiring. To do that, you’ll need a multimeter and a wiring diagram to find all the connections. If you’ve checked the connections and the air still isn’t working properly, then the problem may be with the blower motor itself.
Checking the Blower Motor
Disconnect your car battery and detach the motor from its connector. Unscrew all the screws on the motor and set them aside. Be sure not to lose them, as you’ll need them to reassemble the motor later. Find the retainer clip in the center of the blower wheel and disconnect it from the motor shaft. Set this piece aside as well.
If you find debris in the motor, carefully clean them out. Rodents have been known to get into the fan and stop it from working, so make sure the fan is completely clear of any debris before moving on. Once it’s clean, use an electric parts cleaner on the motor.
Oil the blower motor bearings and check to make sure that the wheel spins freely and all the other parts are working correctly before reassembling the motor and putting it back into your car. Reconnect the battery and turn the car on. If the air still isn’t blowing properly into the cabin of the car, then you’ll need to replace the motor itself.
How Much is a New Blower Motor?
If you’ve discovered that the problem sits with the blower motor itself, then you’ll need to take the time to replace it. The best way to ensure that you’re getting the correct replacement is to take the old motor into the auto parts store and buying a newer, exact model. If you’re unsure about the type of part that you need, double check that you’re getting the correct one that fits the make and model of your car. Most auto parts stores are good at helping you select the right one.
A blower motor for most vehicles is going to cost a lot for the part itself. Depending on the make and model of your vehicle, you could spend between hundreds of dollars for a new blower motor. Factor in the cost of labor if you have a mechanic make the repair, and you should be prepared to pay for the replacement.
Replacing your Blower Motor
Once you’ve bought the correct part, then replacing it is as simple as taking it out. Disconnect electrical connector from the blower motor and remove the retaining screws to the assembly. Pull the assembly box from where it’s been placed in your vehicle, and then pull the blower motor from its housing.
Take the new blower motor and replace it in the same place as the old. Put the assembly and housing back in the same place, and replace the screws. Reconnect the electrical connect and turn your car on to make sure that everything is working properly. Your air conditioning and heater should both be working correctly at all speeds.
What if Something Still Isn’t Working Correctly?
If you’re still having trouble with your air conditioning after you’ve replace the blower motor, then it may be time for you to take your car into a qualified mechanic for another look. While this guide has covered the problems that you likely would experience when checking your blower motor, there’s a chance that you overlooked something that they would be able to help you find.
Replacing a Blower Motor is an Easy One-Day Project
If you’re experiencing a problem with your air conditioning or heating, don’t wait to take a look under the hood and see if your blower motor is going bad. Troubleshooting a failing blower motor doesn’t take too much time and can save you from an even worse problem if the blower motor short circuits.
You can prevent an uncomfortable drive by locating the source of the problem and replacing the part so you’re not driving in a cabin that isn’t climate-controlled during months where extreme heat or cold are the norm.