Sequence of work
1. If the fan does not work with the ignition on at any position of the switch, first check the corresponding fuse No. 25 (see «electrical equipment»).
2. If the fuse is OK, check the fan speed switch by removing the control box.
3. Turn on the ignition.
4. Connect a test lamp or voltmeter to «mass» and check for voltage on the wires connected to the switch. To do this, pierce the insulation with a contact needle.
5. On a black-red wire (voltage supply) the lamp should burn 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, repair the wiring harness or replace the switch.
7. If the wiring and switch are OK, remove the fan.
8. Check the voltage supply to the fan motor by connecting a test lamp or a voltmeter with one wire to «mass», others - to the contact for connecting the green-gray or red wire to the electric motor. If there is no voltage, check the wiring.
9. Check the voltage between the two contacts of the fan motor connection, while setting the fan switch to the position «5». The voltmeter should show 12 V.
10. If there is voltage, but the fan does not work, it is faulty. Replace fan.
11. If there is no voltage, the cause is the fuse.
12. If the fan only works at certain speeds or only at certain speeds «5», The switch resistors may have failed.
13. Remove the block of resistors in the mounting block. Carry out a visual check. If one of the resistors is burned out, replace the entire resistor pack. On vehicles with air conditioning, an electronic speed controller is installed on the side of the fan motor.