Front-wheel drive vehicles have electric fans located near the front of the engine. Rear-wheel drive vehicles have engine-driven fans located in front of the water pump and controlled by a fan clutch.
Engine-driven mechanical fans are most typically found in trucks and SUVs, as these vehicles are usually rear-wheel drive. These fans are thermostatically controlled by a viscous clutch. The clutch is located at the hub of the fan where the air comes in through the radiator.
Front-wheel drive engines are mounted transversely, as engine output goes to the side of the car. This necessitates mounting the electric fan in the front of the engine compartment, usually behind the radiator.