2. Find the relay of the electric motor for the heater fan drive in the mounting block in the engine compartment of the car. Remove this relay and check if it works properly (see chapter Onboard electrical equipment). Replace defective relay.
3. Move the transmission to "R", apply the parking brake and turn the ignition key to the ON position without starting the engine.
4. The heater fan assembly is located under the dashboard of the car, behind the glove box, near the bulkhead of the engine compartment.
5. Move the air supply direction control knob on the heater operation control panel to the FLOOR position (FLOOR), set the fan speed selection knob to position 4. Try to hear by ear whether the air is supplied through the air ducts. If there is air, move the speed control to position 1 and listen again. Repeat the test in each of the handle positions.
Note. The fan speed switch is connected to the electrical circuit of the electric motor from the ground side.
6. If the fan does not function, and all fuses and relays have been checked and are in good condition, you should proceed to checking the electric motor itself. Locate the electrical connector on the back of the fan assembly and use a sharp voltmeter probe to probe the yellow-black wire terminal with the ignition on. This terminal must have a voltage of at least 10 V in any of the positions of the speed control switch, except for the OFF position (Off), otherwise there is a circuit damage in the area between the fuse mounting block and the control panel for the operation of the heater / air conditioner, or between the control panel and the electric motor.
7. If there is voltage on the power supply, but the fan does not function, short the blue-red wire terminal to chassis ground (use a jumper wire with a sharp probe). If the fan does not work when the terminal is grounded, replace the electric motor of its drive, otherwise, check the condition of the circuit in the area between the speed selection switch and the resistor assembly.
8. If the fan only runs at some of the speeds, check its resistor. The resistor assembly is fixed on the fan casing on the right under the instrument panel. There are three resistors on the board that allow the fan to operate in the lower three different speed modes, when the fan is turned on at maximum speed (position 4) current is passed by the devices bypassing the resistors.
9. Remove the resistor assembly and visually assess the condition of its elements (elements must not be melted). Measure the resistance between terminals 1 and 5 of the connector. if the measurement result is outside the range of 5÷3.5 ohms, replace the assembly.
10. If the resistor assembly is in order, but the fan still does not operate at all speeds, you should refer to the materials of Section Onboard electrical equipment and remove the control panel for the operation of the heater / air conditioner. Disconnect the wiring connector from the back of the fan speed selector switch and check the distribution of conductance between the terminals in the different positions of the switch. A defective switch must be replaced.
11. Check the condition of the heater fan relay in the mounting block in the engine compartment of the car. Remove the relay from its socket and check the correct operation of its operation (see chapter Onboard electrical equipment). Probe the contact terminals in the socket of the mounting block with a voltmeter: on terminal 4, the battery voltage must be present constantly, on terminal 1, only when the ignition is on. Terminal 2 must be permanently grounded to ground.