The 2005 Jeep Grand Cherokee hydraulic fan drive (motor) consists of the three major following components: steering flow control valve, fan control valve, and two stage G-rotor hydraulic drive. The hydraulic radiator cooling fan is controlled by the Front Control Module (FCM). A Pulse With Modulated (PWM) signal from the FCM controls the fan speed. There are three inputs to the FCM that determine what percentage of fan speed is required by the vehicle, Engine Coolant Temperature, Transmission Oil Temperature, A/C System Pressure.
The following schematic shows the 2005 Jeep Grand Cherokee Hydraulic Cooling Fan Module Circuit and Wiring Diagram.