"Cross Flow Fan" First, the symptom confirmation, start the engine, press the AC button on the control panel, automatic air conditioning, air conditioning compressor operation, each dashboard air vent blowing cool enough to explain the air conditioning compressor is working properly. Condenser in front of the electronic cooling fans start to run together with the electronic cooling fan speed increases, the gradual increase in noise, sitting in the cab can be clearly heard. Experience has shown that the maintenance of the new electronic cooling fan installed, commissioning, after the engine revolution 10min moving new electronic cooling fan has issued a "whining" noise, no improvement in the symptom. Connection GTl detector self-diagnosis, E38 7 Series chassis models, double-click "IHKA automatic climate control" in the electronic control system diagnostics program main menu, GTl check 'tight corner 0 instrument quick scan of the project, after click "Control module function "button, select IHKA electronic control system, fault information query, no fault codes stored.