Automatic Climate Control, ACC

B2425





Fan control voltage. Short to B+
Fan control voltage. Short to ground

Fault symptoms
Ventilation fan cannot be operated from ACC.

Conditions
Short circuit to ground or B+.





Diagnostic procedure

1. Checking fan control voltage
- Unplug connector: Ventilation fan control : (220).





- Connect test probes as follows:





- Turn the ignition key to ON.





- Increase the fan speed step by step on the ACC/MCC panel.





- The voltmeter should read 0-5 V in short steps from minimum to maximum fan speed.

Is the function correct?
YES
- Replace Ventilation fan control unit.
- Go to step 2.
NO
- Rectify lead in question.
- Go to step 2.





2. Final check
- Delete diagnostic trouble codes in all systems.





- Carry out a function check.
- Evaluate the function check.
- Check that the diagnostic trouble code does not recur.

Does the diagnostic trouble code recur?
YES
- See "Before changing a control module." Before Changing a Control Module

NO
- The steps taken to rectify the fault were correct.