It designed the coolant circulation "220V AC Cooling Fan" system, which has a cooling fan plays an important role. For electric cooling fan control mode for each model used also vary on the combination of the following two failed instance, to understand how the two common "220V AC Cooling Fan" control works and troubleshooting. When the switch is open air, through air-conditioning fan at low speed fan relay control relay so that the cooling fan rotation. 217 relay ground (green / yellow line) and double thermal sensitive switch is connected, once the coolant temperature rose to a certain temperature, double thermal sensitive switch controls the relay Ground, "220V AC Cooling Fan" will enter the high-speed operating state. In addition, the main relay FireWire 217 and FireWire are in control when the ignition is turned armed confused?