Many people complain about the intermittent performance of their car blower motors. It is a fan that connects with the air conditioner and heater of the car and regulates air ventilation.
Car blower motor works intermittently due to a malfunctioning connected motor, broken wires, clogged filters and vents, power circuit failures, broken resistors, and temperature-related damages.
I do not clean my car’s air filters and vents, which leads to intermittent blower performance. It works properly and then suddenly stops due to the following reasons.
| Causes | Solutions |
| Malfunctioning connected motor | Replace motor brushes and bearings |
| Wires break | Replace the wires |
| Clogging of filters and vents | Change broken filters or clean vents and filters |
| Power circuit failure | Replace fuses and relays |
| Broken resistor | Change the resistor |
| Temperature causes damage | Stabilize the blower’s high speed and cut power flow |
Malfunctioning connected motor
Car blower works with an electrically functioning built-in motor. It regulates its speed and performance through power flow.
It comprises bearings and brushes according to their composition. Its excessive usage causes vibrations in the brushes, and they undergo damage.
Its brushes cannot produce the specific force for the blower performance. They cannot regulate magnetism and polarity.
Sometimes, it works and regulates the blower. It sends air into the vehicle cabin. The broken motor reduces its efficiency, and it fails.
The brushes break down due to high temperatures. However, it works when you activate its power flow.
Then, it shuts off, and the current flow disconnects. You can repair this problem and stop its intermittent response.
You can remove these malfunctioning brushes and change them. You can replace them by accessing them in the glove box.
Removing the mounting bracket and bolts is necessary. You can remove them by loosening the bolts.
You can remove the four connecting screws which hold the fan in a specific position. You can adjust a flat screwdriver under the rubber bits and remove them.
You can access dual brushes with specific clips. You can remove the soldered springs and clips.
Then, you can pull the old and malfunctioning brushes and remove them. You can install new brushes and solder the cords and springs.
Sometimes, it shows an intermittent response when the motor bearing cracks. This is because broken bearings reduce its efficiency and alter its response.
Moisture, dirt, and corrosion can break the bearings, and they do not perform. However, you can change these broken bearings and fix the problem.
You can remove the old bearings from the motor by adjusting a puller. You can apply three-dimensional forces on all sides and pull them.
You can install the new bearings and connect them with the seals. Then, add all the screws in the relevant holes and tighten them.
Wires break
The car blower shows intermittent performance when the connected wires break. This is because it connects with the electric circuit of the vehicle.
The power flows through cords and connectors. It has different switches, relays, and cords for optimized efficiency.
It works for a few minutes and stops. Then, its performance continues after a few minutes.
It happens when the electric wires do not connect properly. Their loose connection causes current loss.
Malfunctioning wires cannot maintain their speed. Therefore, it works at a higher speed for 3 to 5 minimum and slows down.
Rusting, excessive use, and variable amperes flow can break the cords. Old cables become loose and cannot supply enough power flow.
Defective wires and harnesses make its speed irregular. In addition, wires degrade and break with time.
Heat exposure and moisture can damage their insulation. In addition, rusting can reduce their connection capabilities.
High heat can break the insulation and melts the electric wires. These damaged wires result in intermittent functionality of the car blower.
You can replace these broken wires by finding them in the dashboard. They are in the instrument cluster and behind the panels.
You can strip and remove them from the connecting points. Then, you can install the new insulated cords for motor stability.
It works at a stable speed and provides better efficiency.
Clogging of filters and vents
Car blower motor has a specific design for maximum airflow. It works with air filters and vehicle vents for proper air circulation.
Sometimes, the debris accumulates inside the vents and filters. In such circumstances, they lose their stable performance.
The clogged filters and vents result in intermittent functionality of the blower. As a result, dust and debris accumulate in the surrounding areas of the fan.
The clogged fan cannot move at a particular speed level. Sometimes, it spins according to the signals and internal force.
Then, it stops rotating, which shows its malfunctioning. The clogged fan can break and undergo electric failures.
It can lead to damage to the built-in electric motor. However, you can replace the broken filters.
Cleaning the vents and filters is beneficial for stabilizing its operation. The filters attach with clips and mounting brackets.
You can pull the clips and remove them. Then, you can install a new filter and re-adjust the clips.
Moreover, you can clean the vents, filters, and motor and remove the dust.
Power circuit failure
The electric circuit of the cars regulates the standard performance of the car blower and its motor. Sometimes, the electric circuit malfunctions when the power flow changes.
The connected fuses malfunction and change their response. It works intermittently once the fuse blows.
The electric motor loses its efficiency. It works for some time and then stops.
However, you can change the blown fuses and stabilize the electric circuit. For example, you can adjust a plier or puller on the fuse and pull it.
You can check the stability of its metallic strips. Broken strips indicate malfunctioning fuses, and you can replace them for the stability of amperes.
You can install a new fuse, push it inward, and fix it with the electric circuit. Sometimes, the power circuit malfunctions when the relays undergo failures.
Relays are high-performance electric switches that withstand electrical pressure. Damaged relays break the motor and blower function intermittently.
You can find the relay in the vehicle hood or underneath the built-in steering wheel. You can disconnect the current flow and remove the relay.
Then, you can install a new relay, fix it and stabilize the current flow in the electric circuit.
Broken resistor
Car blowers comprise specific resistors. The resistors can regulate the rotational motions of the fan.
They can monitor its speeds and identify the changes. Their primary function is voltage regulation in the electric motor of the vehicle blower.
However, heat and rust can damage the resistor. Then, the voltage regulation changes, and blower functionality becomes intermittent.
Overheating causes more damage than corrosion. It reduces the resistance of the resistor. It cannot adjust the speed of the built-in fan.
The airflow and circulation vary inside the vehicle cabin. You can fix the problem by finding the resistors near the car blower motor.
You can disconnect the pigtail, which attaches to the air conditioner, motor, and cooling pipe. You can find the resistor in the fuse box and pull it.
You can remove the mounting screws with a screwdriver. You can use a ratchet for bolt removal and remove the resistor.
Then, you can strip the wires off and cut the connection. Greasing the resistor housing makes the installation easy.
You can install a new resistor and add all the screws. Then, you can tighten them and re-connect the new pigtail.
You can connect it through specific connectors. Its performance stabilizes, which stops its intermittent functionality.
Temperature causes damage
The car blower is a specific fan that sends hot or cool air into the cabin. However, it has different connected parts for its proper regulation.
Continuous power flow can increase the car blower motor temperature. This is because it changes the fan rotation and air circulation changes.
Overheating can break the connectors and damage the wires. In addition, the melted cords cannot supply continuous power to the blower.
It works intermittently, and the vehicle air conditioning and heating system malfunctions. In addition, low fan rotations can produce high heat levels, which cause severe electrical and mechanical defects.
You can fix this fault by stabilizing its speed. Also, you can avoid its slow speed for a long time. You can turn off the power supply of the vehicle.
It provides natural cooling to the fan. Cutting off the power flow is one of the best methods to reduce its overheating when you feel smoke or smell inside the cabin.
The blower and its motor cool down and work at a stable level.
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