A car blower motor can get damaged for several reasons, such as regular wear and tear, accumulation of dirt and dust, or trapping debris in the filters. When any of these issues occur, certain signs indicate that the motor is malfunctioning and needs replacement.
The airflow from the blower may become very weak, or there may not be any air coming out from the AC at all. Alternatively, the blower may not be functioning at all speeds or may be making a lot of noise when turned on. All these signs can indicate that it is time to replace the motor.