Jerry's response is accurate as far as it goes. Yes it will take additional horses to turn the alternator when the electric fan is running, but you will achieve a noticeable gain when the fan is static, which should be most of the time that the Jeep is moving - street time. Slow off road and stop and go will cost you horses. Many electric fans can be pre set to turn on from between 180 and 200 coolant degrees measured at either at the upper radiator hose or via a probe in the readitor near the upper hose connection. They can also be manually cycled.
Silver,'04 Sport, 4.0L, 5sp, D30/D44 tracloc,
3.73, F&R disc, 30x9.50, every available factory option, Bilsteins, Hella, Hurst, KC, K&N,
RCI Racing, Ram Off Road, Roadmaster tow bar.