Blend door actuator: The blend door actuator is responsible for controlling the mix of hot and cold air that enters the cabin. If it fails, it may cause the AC to only blow warm air out of the defrost vents. The blend door actuator is usually located behind the dashboard, just above the blower motor.
HVAC control module: The HVAC control module is the electronic unit that controls the operation of the HVAC system. If it fails, it may cause a variety of AC problems, including the AC only blowing hot air out of the defrost vents. The HVAC control module is usually located behind the dashboard, on the passenger side.
Wiring fault: A wiring fault could cause the AC to only blow warm air out of the defrost vents. Look for loose or damaged wires connecting the blend door actuator, the HVAC control module, and the blower motor. Repair any damaged wires and reconnect any loose wires.
Vacuum leak: In some cases, the AC blower motor could be getting hot because it is getting vacuum leaks.
