Identify a major component of the HVAC system in a vehicle.

The blower motor is a major component of the HVAC (Heating, Ventilation, and Air Conditioning) system in a vehicle because it is responsible for circulating air through the system and into the passenger compartment. This motor drives the fan that moves air over the heater core or the evaporator, depending on whether the heating or cooling function is being used. By controlling the speed of the blower motor, the driver can adjust the airflow and thereby the temperature inside the vehicle, making it essential for maintaining comfort and air quality.

Other components of the HVAC system include the compressor, condenser, and evaporator, but the blower motor is specifically what facilitates the movement of conditioned air into the cabin. In contrast, the other options listed, such as the fuel injector, brake booster, and thermostat, serve different functions in the vehicle's operation and are not involved in the HVAC system. The fuel injector is part of the engine's fuel delivery system, the brake booster aids in enhancing braking efficiency, and the thermostat regulates engine temperature rather than cabin climate.