The electric motor has three speeds. Low frequencies are provided by an additional resistor 5 (pic. 130), fixed with a screw on the left side of the heater radiator casing. The resistor has two spirals - one with a resistance of 0.23 ohms and the second - 0.82 ohms. When both spirals are connected to the power supply circuit of the electric motor, the first fan speed is provided, if a spiral with a resistance of 0.23 Ohm is included, the second speed is provided. When the electric motor is turned on without a resistor, the fan rotor rotates at the maximum third frequency (4000 rpm).
Pic. 130. Scheme of switching on the electric motor of the heater and the heating element of the rear window:
1 - mounting block; 2 - relay for turning on the heating of the rear window; 3 - ignition switch; 4 - heater motor switch; 5 - additional resistor; 6 - heater electric motor; 7 - rear window heating switch; 8 - a combination of devices with a control lamp for heating the rear window; 9 - rear window heating element.
If the electric motor works intermittently, then it is necessary to check the power supply wires and their connections, the serviceability of the heater switch, and also clean the electric motor collector with fine-grained sandpaper and check the condition of its brushes. It is not necessary to remove the electric motor from the vehicle to clean the manifold. It is enough to remove only the cover with the brush holder by unscrewing the two fastening screws and first removing the protective cover from the electric motor.