Ventilation Fan Control Panel Not Functioning

Ventilation Fan Control Panel Not Functioning

Fault symptom
Ventilation fan control panel not functioning.

Diagnostic help
Do not use thin jumper leads as the fan operates with high current.
The fan commutator must not be lubricated at all.
There is a risk of short-circuiting the poles.

Diagnostic procedure

1. Selecting fault symptom
- Which fault symptoms does the car have?

VENTILATION FAN COMPLETELY NON-OPERATIONAL
- Proceed to step 2.

FAN SPEED POSITION 1 NOT FUNCTIONING
- Proceed to step 6.

FAN SPEED POSITION 2 NOT FUNCTIONING
- Proceed to step 8.

FAN SPEED POSITION 3 NOT FUNCTIONING
- Proceed to step 10.

FAN SPEED POSITION 4 NOT FUNCTIONING
- Proceed to step 12.






2. Checking fuses
- Check that fuse 3 is operational.

Tests OK?
YES
- Proceed to step 3.
NO
- Replace Fuse 3
- Proceed to step 14.






3. Check switch power supply
- Unplug the connector: Switch, ventilation fan (35)






- Turn the ignition key to the ON position.






- Connect a test lamp between pin 2 in the female connector and a good grounding point.






- The test lamp should light up.

Tests OK?
YES
- Proceed to step 4.
NO
- Repair the lead between the ventilation fan switch, pin 2 and fuse 3.
- Proceed to step 14.






4. Checking fan grounding connection
- Unplug the connector: Motor, ventilation fan: (36)






- Connect test lamp 86 11 857 between B+ and pin 5 on the female connector.






- The test lamp should light up.

Tests OK?
YES
- Proceed to step 5.
NO
- Repair the lead between the ventilation fan resistor and ground connection.
- Proceed to step 14.






5. Checking fan motor function
- Bridge between B+ and male connector pin 3. Use cable with 6 square mm cross-sectional lead area.






- Bridge between the male connector pin 5 and a good grounding point. Use cable with 6 square mm cross-sectional lead area.






- The fan should start and operate at full speed.

Tests OK?
YES
- Change : Switch ventilation fan.
- Proceed to step 14.
NO
- Check the male connector as well as the leads between the male connector and the fan. If the connector/leads are functioning, change ventilation fan motor.
- Proceed to step 14.






6. Checking control voltage to fan resistor
- Unplug the connector: Motor, ventilation fan : (36)






- Connect a test lamp 86 11 857 between pin 1 in the female connector and a good grounding point.






- Turn the ignition key to the ON position.
- Put the ventilation fan switch in position 1.
- The test lamp should light up.

Tests OK?
YES
- Change : Resistor ventilation fan
- Proceed to step 14.
NO
- Proceed to step 7.

7. Checking wiring.
- Check that the lead between ventilation fan motor, pin 1 and ventilation fan switch pin 1.

Is the lead functioning?
YES
- Change: Resistor ventilation fan
- Proceed to step 14.
NO
- Repair the lead in question.
- Proceed to step 14.






8. Checking control voltage to fan resistor
- Unplug the connector: Motor, ventilation fan (36)






- Connect a test lamp between pin 2 in the female connector and a good grounding point.






- Turn the ignition key to the ON position.
- Put the ventilation fan switch in position 2.
- The test lamp should light up.

Tests OK?
YES
- Change: Resistor ventilation fan
- Proceed to step 14.
NO
- Proceed to step 9.

9. Checking wiring
- Check that the lead between ventilation fan motor pin 1 and ventilation fan switch pin 1.

Is the lead functioning?
YES
- Change: Resistor ventilation fan
- Proceed to step 14.
NO
- Repair the lead in question.
- Proceed to step 14.






10. Checking control voltage to fan resistor
- Unplug the connector: Motor, ventilation fan : (36)






- Connect test lamp 86 11 857 between pin 4 on the female connector and a good grounding point.






- Turn the ignition key to the ON position.
- Put the ventilation fan switch in position 3.
- The test lamp should light up.

Tests OK?
YES
- Change : Resistor ventilation fan
- Proceed to step 14.
NO
- Proceed to step 11.

11. Checking wiring
- Check that the lead between ventilation fan motor, pin 4 and ventilation fan switch pin 6.

Is the lead functioning?
YES
- Change: Resistor ventilation fan
- Proceed to step 14.
NO
- Repair the lead in question.
- Proceed to step 14.






12. Checking control voltage to fan resistor
- Unplug the connector: Motor, ventilation fan: (36)






- Connect test lamp 86 11 857 between pin 3 in the female connector and a good grounding point.






- Turn the ignition key to the ON position.
- Put the ventilation fan switch in position 4
- The test lamp should light up.

Tests OK?
YES
- Change Resistor ventilation fan
- Proceed to step 14.
NO
- Proceed to step 13.

13. Checking wiring
- Check that the lead between ventilation fan motor, pin 3 and ventilation fan switch pin 3.

Is the lead functioning?
YES
- Change : Resistor ventilation fan
- Proceed to step 14.
NO
- Repair the lead in question.
- Proceed to step 14.






14. Final check
- Erase the diagnostic trouble codes from all systems.
- Check function.

Tests OK?
YES
- Actions taken to rectify problem were correct.
NO
- See Electronic Climate Control, Testing and Inspection.
Testing and Inspection