why on my 04 sedan do i have an electric fan in front of my rad and a mechanical one behind it? whats the point?

 

One fan is primarily for radiator, other one is for the A/C. The electric one sits in front of the A/C condenser.

 

is the one for the ac really neccissary?

 

When you are sitting still, as in parked or at a stoplight for example, the air that would normally be moving past the condenser is no longer moving past it since you are not moving through the air. The Electric fan helps BOTH the condenser AND the Radiator stay cool or at least exchange the heat they are gathering. This is all automated and therefore you will not always see the Electric Fan operating, only when your car determines it is needed.