Code 22A

Command

Ventilation fan - testing

Testing
ISAT scan tool command: 22A

Display shows:
Ventilation fan - speed control, signal 0 - 5 V.

WARNING : The cooling unit for fan motor speed control is live (1.5-12 V, depending on motor speed) and must never be connected to ground.


Action
If the ventilation fan is not working or the ACC control module cannot control its speed, take the following action:

1 Check the ventilation fan fuse.
2 Check the ventilation fan control signal from the Automatic Climate Control (ACC) control module (pin 14 and ground). Vary speed using the fan speed buttons in order to change signal level.
3 If the value of control voltage is incorrect, try with a new ACC control module.
4 If the control signal for fan speed is normal, unplug the ACC control module's 39 pin connector and check for open circuit between pin 14 on the connector and pin 2 on the speed control.
5 If there is no fault in the connection between the ACC control module and the fan's speed control, check supply voltage to pin 1 on the fan speed control and ground connection on pin 4.
6 If there are no faults in supply and ground connections: Disconnect speed control and short between pins 3 and 4. If the motor now works, the fault may be in the fan speed control. Reinstall all connectors and restart the system. If the fault remains, try with a new speed control.
7 If the motor does not work, even with the speed control shorted: Switch off the ignition and wait for 35 seconds. Unplug the ACC control module's 39 pin connector and the connector on the fan speed control. Disconnect the 2 pin connector 59 and interconnect pins 1 and 2. Check if there is an open circuit or short circuit to ground by measuring resistance on the cables to connector 59 between pins 1 and 2 on the ACC control module's connector and the fuse board with fuse 6 removed.
8 If the reading to connector 59 is correct, the fault may be in the motor. Reinstall all connectors and restart the system. If the fault is still present, try with a new motor.










Action
1 Check the fan's output signal on pin 38 or 39 on the ACC control module. Manually vary speed using the buttons for fan control.
2 If the output signal is correct, unplug the ACC control module's 39 pin connector and check the resistance in the rear door fan motor windings. Reading should be <80 Ohm. If resistance is correct, reinstall connectors and restart the system in order to check if the fault is still present.
3 If motor resistance is incorrect, check the cable between the motor connector and the ACC control module's 39 pin connector, and if the resistance is correct, try with a new motor.
4 If the output signal from the fan is incorrect, carefully check the 39 pin connector and then try with a new ACC control module.