1. Blend Door Actuator: The blend door actuator controls the air flow from the different vents. If the actuator is faulty, it may not be opening the correct vent, resulting in air only coming from the defrost vent.
2. Temperature Sensor: The temperature sensor in the dash is responsible for controlling the temperature of the air coming out of the vents. If the sensor is faulty, it may not be properly detecting the temperature, causing the system to only blow out cold air from the defrost vents.
3. Vacuum Lines: The vacuum lines in your vehicle's HVAC system are responsible for controlling the operation of the vents and flaps. If one or more of these vacuum lines are disconnected, cracked, or damaged, it can prevent the vents from changing.
4. Control Panel Switch: The vent selector switch on the control panel may be faulty, causing it to be stuck on the defrost setting.
To accurately diagnose the root cause of the problem, it is recommended to have your vehicle inspected by a professional mechanic or HVAC specialist who can identify the specific component that is causing the issue and make the necessary repairs.
