1, the vehicle has just started and the engine temperature has not yet risen.
2. Insufficient coolant will cause the vehicle air conditioner to be not hot.
3. The water pump is damaged, resulting in the failure of the coolant circulation system.
4. The heater water tank is blocked.
5, radiator fan failure, radiator fan often rotates continuously to dissipate heat, resulting in the coolant in the water tank can not be heated.
6. Solution: Clean the air conditioning filter element to ensure its outlet wind speed, disassemble, clean or replace the blocked warm air water tank, and replace the faulty thermostat and water temperature sensor.