Why does the car make noise when the heater is turned on? How to repair?

It is caused by damage to the heater motor; the solution is as follows;\x0d\First; remove the heater, open the heater casing, and check whether there are foreign objects in the fans on both sides of the motor. If there is any foreign matter, it can be cleared\x0d\Second; open the motor and check the power. Check whether the clearance between the bearings on both sides of the machine is too large. If it is too big, it will be ok. \x0d\Third; Check whether there is a boring phenomenon between the rotor and the spindle. If there is a boring phenomenon, it is recommended to replace the motor. \x0d\Fourth; The heater motor must be maintained before use and the motor bearings must be filled with oil. Clean the heater water tank.