* Low coolant level: If the coolant level is low, the heater core will not be able to transfer heat from the engine to the air flowing through the vents. Check the coolant level and add more if necessary.
* Faulty thermostat: The thermostat is a valve that controls the flow of coolant through the engine. If the thermostat is stuck open, the coolant will not reach the heater core and the air flowing through the vents will be cold. Check the thermostat and replace it if necessary.
* Blocked heater core: The heater core is a small radiator that transfers heat from the engine coolant to the air flowing through the vents. If the heater core is blocked, the air flowing through the vents will be cold. Check the heater core for blockages and clean it if necessary.
* Faulty blend door actuator: The blend door actuator is a motor that controls the position of the blend door, which mixes hot and cold air to control the temperature of the air flowing through the vents. If the blend door actuator is faulty, the blend door may not be in the correct position and the air flowing through the vents will be cold. Check the blend door actuator and replace it if necessary.
If you have checked all of these things and the problem persists, you should take your car to a mechanic for further diagnosis.
