What Causes a Car's Air Conditioner to Blow Cold Air Instead of Heat?
1 Answers
Car's air conditioner blowing cold air instead of heat is mainly caused by the following reasons: Engine Coolant Temperature: First, check whether the engine coolant temperature is normal. If it remains at a low temperature and fails to reach the operating temperature, the heating system will definitely not produce warm air. In this case, focus on checking whether the thermostat is stuck in the large circulation state or whether the coolant temperature sensor signal is accurate. Repair or replace the faulty component as needed. Temperature Difference Between Inlet and Outlet Hoses: Pay special attention to whether there is a significant temperature difference between the inlet and outlet hoses in front of the heater core. If such a difference exists, it is certainly due to a clogged heater core. Coolant Flow Rate and Temperature: Check whether the flow rate and temperature of the coolant entering the heater core meet the requirements. The temperature can be measured using an infrared thermometer to detect differences in pipeline temperatures, while the flow rate can be assessed through diagnostic data and fault storage from a diagnostic tool. Common issues include a faulty water pump, damaged heater flow valve, or a malfunctioning coolant circulation valve. Air Lock in the Cooling System: Check whether there is an air lock in the cooling system. A common cause is failing to bleed the system after replacing the coolant. A more unusual cause could be a damaged cylinder head gasket. Use standard coolant bleeding methods to further confirm the issue.
