B2437

Rear door fans, open/short circuit to ground/BPV.

Conditions
B2437: Short circuit to ground.
B2438: Open/short circuit to BPV.

Action
1 Connect the ISAT scan tool and read "REAR DOOR FANS".
The values are displayed in volts.
As the rear door fans are switched off, 0.0 Volt is displayed. When the rear door fans are activated, voltage varies between approx. 5 - 10 volts, depending on selected fan speed.
2 Check which rear door fan is not working.
If the left-hand rear door fan is not working, proceed to point 3.
If the right-hand rear door fan is not working, proceed to point 7.







3 Unplug the connector (H2-37) beside the rear door fan and measure the voltage between pin 1 and ground.
Press the button on the Automatic Climate Control (ACC) control module panel for activating the rear door fans and read the value.
The correct reading should be about 5 - 10 V. Compare with point 1.
If the reading is incorrect, proceed to point 4.
If the reading is correct, proceed to point 5.
4 Check the wiring harness between pin 9 on the ACC control module and pin 1 in connector H2-37 for open/short circuits.
Localize and remedy the fault.
If there is still no voltage, proceed to "Action Before Changing A Control Module". Before Changing a Control Module
5 Check the wiring harness between pin 2 in connector H2-37 and ground for open/short circuits.
Localize and remedy the fault.
6 Change the left-hand rear door fan.







7 Unplug the connector (H2-29) beside the right-hand rear door fan and measure the voltage between pin 2 in the connector and ground. Press the button on the ACC control module panel to activate the rear door fans and read the value.
The correct reading should be about 5 - 10 volts. Compare with point 1.
If the value is incorrect, proceed to point 8. If the value is correct, proceed to point 9.
8 Check the wiring harness from pin 10 on the ACC control module to pin 1 in connector H2-29 for open/short circuits.
Localize and remedy the fault.
If there is still no voltage, proceed to "Action Before Changing A Control Module". Before Changing a Control Module
9 Check the wiring harness between pin 2 in connector H2-29 and ground for open/short circuits.
Localize and remedy the fault.
10 Change the right-hand rear door fan.