How To Diagnose Blower Motor Trouble And Replace A Failed Motor

The blower motor is what moves the air inside your car's air conditioning and heating system. If it fails, your air conditioner or heater won't blow air when you adjust the dash controls. Fortunately, it is an easy fix on most vehicles to replace the blower motor, and the job can be performed in less than an hour's time, in most instances. Below is more information on diagnosing blower motor problems and what you need to do to perform the replacement yourself:

How to rule out a defective blower motor resistor or blown fuse

While a failed blower motor is not unusual, you should be sure that the blower motor itself, and not some other issue, is the actual problem. A failed blower motor resistor is also a common cause for trouble with the fan. The resistor is what controls the amount of current flowing to the motor, depending upon the user's desired fan speed setting. If your blower motor operates at only the highest fan speed setting, but does not function at the lower fan speed settings, then the likely trouble is a defective blower motor resistor.

Should the blower not turn on at all, then you will need to rule out a blown fuse before attempting any other repairs. The fuse for the blower motor will be located inside the car's fuse panel or inside the engine compartment; there is usually a fuse diagram next the panel showing where the fuse is located, and simply swapping out the fuse with a replacement will let you know if that solves the problem.

How to replace the blower motor

After ruling out a blower motor resistor failure or blown fuse as the problem, you will need to remove the blower motor for further testing and possible replacement:

1. Locate the blower motor - Vehicle blower motors are located behind the dash, typically near the glove compartment. To locate your vehicle's blower motor, position yourself beneath the dash on the passenger side and look upward at the visible components and parts. You will probably need a flashlight to help you see clearly. The blower motor housing will be round and fastened to the air conditioning and heating duct.

If you can't locate the blower motor housing, it may be obscured by the glove box. In that case, locate the screws that hold the glove box in place and remove them. Pull the glove box out of the way, being careful not to break any plastic tabs or damage any under-dash wiring.

2. Remove the blower motor - Once you locate the blower motor housing, find the wiring harness that attaches to the motor and gently pull it free from the terminal. Next, find the screws that hold the housing in place, and remove them; be sure to support the motor at the same time to prevent it from falling. Carefully pull the motor and attached fan out from behind the dash.

3. Test the blower motor - After the motor is pulled free, you can perform a test to be sure it is defective. Attach positive and negative 12-volt jumper wires to the car's battery, then touch the lead ends to the blower motor's terminal connectors. If the motor doesn't respond, then you can be sure the motor has failed and will need replacing.

4. Install a new blower motor - Obtain a new blower motor that fits the make and model of your vehicle from a dealer or auto parts supplier. Position it inside the space underneath the dash where the old motor was located, being careful to line up screw holes. Insert the screws and tighten them to hold the blower motor in position. Next, plug the wiring harness back into the terminal connector and replace the glove box if you removed it to gain access to the motor. Test the motor for proper operation by turning the fan speed control to all its speed settings.

For more information on resolving blower motor trouble, contact an auto repair shop like Jensen Tire & Auto.

About Me

Understanding Car Maintenance

About a year ago, I was surprised when my vehicle died suddenly. Sure, I hadn't been taking care of the annual maintenance, but I figured that those items were just part of the decreasing manufacturer's liability. Unfortunately, after the vehicle was checked out, the mechanics told me that it needed thousands of dollars worth of repairs. I was frustrated, but I knew that I needed to learn more about car maintenance to avoid problems like that in the future. I started reading up on maintenance, and I was able to track down a few issues. This blog is all about understanding car maintenance and avoiding mechanical problems.

Archive