1. The air heating heater in the car has several vents on the windows, and the heated air is sent to the car through the vents. Turn on the heater and face the vent with your hand. If you can feel the air and it is hot, then the air heater is working normally.
2. Turn off the radio or other devices, park the car in a quiet place and listen to the sound of the heater fan turning. If you do not hear the sound of the fan rotating or the air moving, the heater is broken. If you can feel the hot air from the vent, but the hot air is not blowing, it means that the motor of the air heater is broken.
3. If you can't hear the fan rotating or can't feel the air flow, and there is no heat, it means that the entire air heater may be broken.