When a car's blower motor resistor is damaged, the most noticeable symptom is that the fan operates at speed 4, while speeds 1, 2, and 3 have no airflow. This occurs because the blower motor primarily switches speeds by integrating different resistance values in the circuits for speeds 1, 2, and 3. If the resistor is damaged and becomes non-functional, it naturally won't control the fan speeds at 1, 2, and 3. However, speed 4 operates directly and, thus, remains functional.
If the blower motor doesn't work at speeds 1, 2, or 3 but operates normally at speed 4, the solution typically involves replacing the blower motor resistor. You can visit a 4S shop or a specialized repair shop for replacement. The cost of replacement is generally inexpensive, often just a few tens of dollars. The replacement process is quick and straightforward.
Regular maintenance of the blower motor is essential to prevent excessive operational resistance from damaging the resistor. Periodically, disassemble the blower motor assembly and clean the fan blades. If any blade is damaged, consider replacing it. It's advisable to lubricate the motor bearings with grease periodically and inspect all circuits for any damages or loose connections.
Additionally, we don't highly recommend car owners replace the blower motor resistor on their own. Replacing it involves car circuitry, and choosing the appropriate model for the blower motor resistor is crucial. Improper handling can potentially harm the vehicle. However, if car enthusiasts have a certain level of technical expertise and understand circuitry, they can consider performing the replacement themselves.
