Turn on the warm air of about 50 degrees, and then try to see if there is any peculiar smell. If yes-the leakage of the heater water tank can be determined as100%; If it is not-try to raise the temperature to the external radiator fan (90 degrees), try to smell, 1 foreign objects fall from the air outlet or defrosting port, 2 the heating device is aging, and the aging plastic will reach the softening critical point because the water tank temperature reaches nearly 100 degrees, and the smell is hose smell.
Give points after efforts are effective,