Is it normal for the pointer of the automobile thermometer to drop when the warm air pointer is turned on halfway?

The question you mentioned is completely normal. First of all, heating warm air in winter will consume the heat of the engine. If the displacement of the engine is relatively small, it is easy for you to say this. Because the heat generated by engine operation is not enough to offset the heat consumed by heating air, it is normal that the water temperature will drop when you heat air. If it is a large displacement engine or when driving at high speed, such a problem will not occur. You said that this kind of situation will only appear when the warm air is turned on under the condition of small displacement+low temperature+low speed driving. This is a normal phenomenon, don't worry.