The vehicle is equipped with a heater fan motor with permanent magnet excitation. An additional resistor is installed in the power supply circuit of the electric motor to obtain different speed values. It includes three spirals and a fuse. When the current passes through all three spirals, the 1st speed of rotation of the heater fan is provided, through two spirals - the 2nd speed, through one - the 3rd speed. When the electric motor is turned on without an additional resistor, the fan motor armature rotates at the maximum 4th speed.
If the motor fails, replace it with a new one. The only possible repair of the electric motor is to clean the collector.