How To Test a Car's Blower Motor

Owning a car entails responsibility in maintaining all parts of your car and keeping it in good running condition. Among the important parts under the hood is the blower motor, which helps circulate air throughout the passenger cabin. A car’s blower motor is also responsible for diffusing hot air from the engine. When the blower motor gets busted, your car might have a higher likelihood of overheating, especially in heavy traffic or in hot weather. You will need to make sure your blower is in good condition, to ensure safety.

  • Listen to the sound produced by the motor. In essence, a normal blower motor produces sound. During normal operation, and while idle, you should hear the car’s blower motor operating. Since most cars come with noise insulation, open your window and observe the noises coming from the engine. The fan usually starts operating at a certain temperature, and will alternate between on and off, depending on the engine temperature. If you do not hear the fan running at all, then it may be an indicator of a damaged fan. This might also mean a blown fuse, a bad resistor, or damaged wiring.
  • Check if the fuses are blown. Open your car’s engine bay and locate the fuse box. The cover will usually have a legend, indicating which fuse is meant for which part. Remove the fan fuse and replace it with a similar-rated fuse. Turned on the engine, and observe whether the fan is now running. If the new fuse blows, then the problem is a short circuit. Another possible cause of the problem might be dirty brushes inside the fan motor. The fuses may stay for a while and then blow later on, because of the added strain. If this is the case, then have the motor’s brushes replaced immediately.
  • Remove the motor from its mount. If the fuses are operating properly, take the motor out of its mount, and do a visual inspection. Check if there are any loose wires. If the wires are okay, take the jumper wires and hook them to the motor. Have one wire attached to a ground, and another wire attached to a power source. If the motor will not work, then it needs replacement.
  • Feel for air flowing out of the vents. If the fuses and the motor are properly operating, turn on the heat. Feel the vents and check if there is air coming out. Turn the air conditioning on and check again if there is air. If the motor is running, but no air is coming out of the vent, it might be possible that the motor has been clogged.
  • Check the air controls. You can use a diagnostic tool to check the air control. This will usually be available for rent at an auto supply store. You will have to refer to your car’s maintenance manual to check for the error codes, though.

A defective blower motor will result in poor performance of your heating and air-conditioning system. This will bring discomfort to the passengers most especially in extreme weather. Make it a point to have your air conditioning system tested during your car’s periodic maintenance service schedules.


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