2. Check the heater control valve. The heater control valve regulates the flow of hot coolant to the heater core. If the valve is stuck closed, no hot coolant will be able to reach the heater core.
3. Check the heater core hoses. The heater core hoses carry hot coolant from the engine to the heater core and back again. If the hoses are kinked or blocked, the heater core won't be able to circulate enough hot coolant.
4. Check the blend door. The blend door controls the mix of hot and cold air that is blown into the cabin. If the blend door is stuck in the closed position, no hot air will be able to enter the cabin.
5. Check the blower motor. The blower motor circulates the air through the heating system. If the blower motor is not working, no air will be blown through the heater core and into the cabin.
6. Check the electrical connections. The heater system relies on a number of electrical connections to function properly. If any of these connections are loose or corroded, the heater system may not work properly.
