The hydraulic fan (below picture) used on 2002 Jeep WG Grand Cherokee 4.7L replaces both the electric fan and the engine driven mechanical fan. The hydraulic cooling fan is integral to the fan shroud and is located between the radiator and the engine. The power steering pump supplies the hydraulic fluid and pressure to rotate the cooling fan blade, while the electrical part of the fan is controlled by the JTEC.
Hydraulic Radiator Cooling Fan and Fan Drive: 1. Power steering fluid cooler; 2. Radiator; 3. High pressure line from steering gear pump to hydraulic fan motor; 4. Hydraulic fan motor; 5. High pressure line from hydraulic fan motor to steering gear; 6. Fan shroud
The 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 fan and drive is not serviceable. Therefore any failure of the fan blade, hydraulic fan drive or fan shroud requires replacement of the fan module because the fan blade and hydraulic fan drive are matched and balanced as a system and servicing either separately would disrupt this balance.