Sequence of works
1. If the fan does not work with the ignition on in any position of the switch, first of all you should check the corresponding fuse No.25 (see "Electrical equipment").
2. If the fuse is OK, check the fan speed switch by removing the control unit.
3. Turn on the ignition.
4. Connect a test lamp or voltmeter to the "ground" and check for voltage on the wires leading to the switch. To do this, pierce the insulation with a contact needle.
5. On the black and red wire (voltage supply) the lamp should light in any case, and the voltmeter should show the battery voltage value. On wires with green insulation with additional stripes of a different color - only with the corresponding switch position.
6. If anything does not function as described above, troubleshoot the supply wiring or replace the switch.
7. If the wiring and switch are OK, remove the fan.
8. Check the voltage supply to the fan electric motor by connecting a test lamp or voltmeter with one wire to the ground and the other to the green-gray or red wire connection contact to the electric motor. If there is no voltage, check the wiring.
9. Check the voltage between the two fan motor connection contacts, with the fan switch set to position "5". The voltmeter should show 12 V.
10. If there is voltage but the fan does not work, it is faulty. Replace the fan.
11. If there is no voltage, the problem is in the fuse.
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12. If the fan only works at some speeds or only at speed "5", the switch resistors may be faulty.
13. Remove the resistor block in the mounting block. Perform a visual inspection. If one of the resistors is burnt out, replace the entire resistor block. On vehicles with air conditioning, an electronic speed controller is installed on the side of the fan motor.