- Malfunctioning blend door: The blend door is responsible for regulating the temperature of the air coming out of the vents. If the blend door is not working properly, it may be stuck in one position, causing cold air to come out of one side and warm air out of the other.
- Faulty temperature control sensor: The temperature control sensor sends a signal to the climate control unit to regulate the temperature of the air. If the temperature control sensor is faulty, it may be sending an incorrect signal to the climate control unit, causing the wrong temperature of air to come out of the vents.
- Low coolant level: If the coolant level is low, the heater core will not be able to properly heat the air coming through the vents. This can cause cold air to come out of one side of the vents and warm air out of the other.
- Clogged heater core: The heater core is responsible for heating the air coming through the vents. If the heater core is clogged, it will not be able to properly heat the air, causing cold air to come out of one side of the vents and warm air out of the other.
